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Chapter 7 - Health factors affecting settlement of the American humid tropics

Parasitic diseases
Viral diseases
Diseases produced by Bacteria, Rickettsia, and Spirochaetes
Mycotic diseases
Fauna harmful to man
Medicinal plants

The determination of many South American governments to exploit the known and unknown resources of their rain forests has led to a proliferation of diseases which threaten man's safety in the jungle. Governmental pressure to exploit the resources of the rain forest has forced man to move into the Selva and confront conditions to which he is neither accustomed nor adapted. Here he is exposed for the first time to diseases characteristic of the rainy tropics, while at the same time he is introducing new diseases to indigenous Selva populations. The scarcity of epidemiological studies and the relative ignorance of health professionals about tropical disease contribute to the persistence of these pathologies and reduce the possibility of controlling and eradicating them. Consequently, planning and development programs in the Central Selva and elsewhere in the humid tropics must give high priority to disease prevention and teach settlers the natural healing properties of the flora and fauna of their region. Such an effort may permit man to live safely in ecosystems to which he is not thoroughly adapted.

Five major types of invaders threaten human bodies in the Peruvian Selva: parasitic, viral, bacterial, mycotic (fungal) and animal (those caused by insects, snakes and fish). Among the most serious problems confronting newcomers to Amazonia are parasitic diseases, because they are so difficult to control. In virgin jungle, human parasitosis should not exist; but if a parasite-free population comes into contact with native populations that are affected by many parasites, infection of the newcomer is inevitable. On the other hand, a wide range of viral infections and such diseases as measles, hepatitis, and poliomyelitis represent a danger to native communities, since these communities have not been exposed to them and their immunity is very low. Tuberculosis and other respiratory diseases are also a common threat to people already weakened by parasites, anemia and malnutrition. Furthermore, various fungi can cause pulmonary diseases, particularly those that produce systematic mycosis (South American blastomycosis, histoplasmosis, and asperfillosis).

Bacterial and mycotic skin and genera) infections abound in the humid tropics, where unsanitary living conditions, skin moisture, and the lack of adequate health care transform individuals into sources of infection and encourage the spread of disease.

Insect bites can be very serious, especially for people who are in Amazonia for the first time and have not developed immunity to them. Insect bites can produce intense cutaneous allergic reactions, opening the skin to allow the introduction of bacteria, such as yellow fever, malaria, chagas disease, and leishmaniasis.

Parasitic diseases

As people migrate from the mountains to the Selva, they bring their parasites with them. Parasitic diseases occupy first place among the diseases of the humid tropics. They are widely distributed and represent a serious health problem. Because sanitary conditions in the jungle are inadequate, people are infested by almost all of the intestinal protozoans, particularly Entomoeba coli, Endolimax nana, lodamoeba butschlii, and Dietamoeba fraglis. The most medically important, however, is Entamoeba histolytica, widely known as the cause of amoebic dysentery. A high percentage of the population of the Andes is infested by E. histolytica, which actually lives commensally with man, feeding on food waste in the colon that still contains a large amount of carbohydrates. There, it reproduces and encysts, before being eliminated in the feces. In the absence of sewage systems these cysts contaminate the soil; thus, the food and water that sustain man are converted into sources of infection that affect great numbers of people, while flies and other organisms help spread it. Even one infected person can be responsible for the spread of E. histolytica in the jungle, because the climatic conditions, the level of nutrition, and the presence of other jungle intestinal parasites, particularly nematodes and bacteria that damage the large intestine, all favor the spread of the disease.

Besides E. histolytica, which can be present in 20 percent or more of mountain populations, another parasite, Balantidium coli, is also quite common in swine and occasionally affects man (Lumbreras, 1954a, 1954b). Studies carried out on indigenous populations in the mountains found that 15 percent of the people had the parasites. Fewer were infested among jungle populations, but there the parasite's effects are more serious. B. coli spreads the same way as E. histolytica: a person from the mountains brings it with him when he enters the jungle; it attacks persons whose colon mucosa are damaged through other causes such as bacteria or helminth parasites like Trichiuris trichiura, which allows B. coli to penetrate the mucosa, causing ulcers and symptoms similar to E. histolytica.

Giardia lamblia, another widely distributed intestinal protozoan, can cause digestive problems in children, notably diarrhea and malabsorption, and it can lead to dehydration, which, if not treated promptly, can cause malnutrition and death. Isospora belli is a protozoan that affects the cells of the mucosa in the small intestine. It exhibits a life cycle similar to malaria that includes sporozoites, macro and microgametes, and cysts that are eliminated in feces and that contaminate the soil.

Protozoans that attack other tissues and organs besides the intestine warrant special attention. Within this group are flagellates, among which stand out trypanosomes, leshmanias, and sporozoans, the most important of which causes malaria and toxoplasmosis. Various wild vectors of Trypanosoma cruzi, the source of Chagas' disease or Trypanosomiasis americana, have been identified in the Central Selva (Lumbreras, 1972; Lumbreras, et al, 1975). Known vectors are Panstrongylus geniculatus, Rfiodnius robustus, Rhodnius pictípes, and Eratyrus mucronatus, all of which have been found in parts of the Central Selva infested by the parasite.

Vectors of this disease generally live in palm trees (as has been demonstrated in Venezuela) and occasionally enter homes, where they can attack man and domestic and semi-domestic animals. It is well known that Trypanosomiasis americana is azoonosis and, therefore, can infect other animals that serve as reservoirs, such as monkeys, marsupials, bats and other mammals and birds. Some vectors, such as Rhodnius robustus, can complete their reproductive cycle within a home, where the females deposit eggs and the emerging larvae feed on man and domestic animals. R. herreri has been found to do this in the Huallaga and Marañon valleys; R. robustas, on the other hand, does not complete its life cycle in homes, even though adult females frequently enter them,

Two forms of leishmaniasis exist in Peru; the cutaneous form, Uta, which predominates in the Andes, and the cutaneous-mucosa form, Espundia which predominates in the jungle (Hinojosa, 1982; Lumbreras, et al, 1975). Throughout both the low and high forests in Amazonia, the clinical cutaneous-mucosa form is found - attributed to Leishmania brasiliensis, dominant in the Central Selva, and to Leishmania brasiliensis guyanensis.

The genus Lutzomya is generally the vector of leishmaniasis, notably the species L. peruensis which appears to exist in the Amazon region. Besides this genus, Psychodopygus and Brumptomyia have been considered possible vectors in other countries. In Peru, however, these genera have not been yet determined to be jungle leishmaniasis vectors, though they are found in the country. The habits and habitat of the disease's vectors need to be investigated, so that they can be controlled. It is also important to know which mammals serve as reservoirs; suspected are the rodents Cryzomys, Dasyprocta, and Neacomys; marsupials, and sloths.

Jungle leishmaniasis is a zoonosis; thus man is an occasional victim. The disease generally appears in people who work in the forest, including coffee workers, rubber workers, trailblazers for petroleum geologists, and those who pan for gold. In populations settled in cleared areas, leishmaniasis tends to disappear because the vectors disappear.

Toxoplasmosis is another protozoosis frequently found in humid jungles, particularly in the high forest (Lumbreras and Muñoz, 1963, Lumbreras et al, 1971). In some parts of the high Amazon region, 75 percent or more of the population are reported to possess antibodies, The cat is the definite host, but all other animals, including birds, are susceptible to infection. Man can acquire the infection through eating insufficiently-cooked meat containing toxoplasma cysts.

Malaria and its Central Selva agent, Plasmodium vivax and Plasmodium malariae, constantly threaten jungle populations. In 1969,3,168 cases occurred, with a morbidity rate of 24 and a mortality rate of 0.3 per 100,000 inhabitants when the total population was 12,998,100. In 1980, there were 80,000 cases in a Peruvian population of 17,779,500 people, with morbidity being 450 and mortality 4.0 per 100,000 people.

Malaria flares up repeatedly in the humid tropics because eradication and control campaigns such as insecticide spraying have been difficult to maintain. Patients acquire malaria in the tropics then carry it to other regions, particularly the coast, and it becomes necessary rapidly to extinguish the disease in these areas to prevent further spread. In the Ene river region, malaria is hyperendemic and both types of Plamodium, P. vivax and P. malariae, occur there, with the latter predominanting (Cantella et al, 1968). Forty species of anopheles mosquitoes, vectors of malaria, have been described in Peru, only three, however, are significant; A. pseudopunctipennis which is distributed throughout except in the low jungle; A. Benarrochi which predominates in the low jungle, and A. darlingi which is found along the Brazilian border. A. rangeli, in the high jungle, and A. oswaldoi, in the low jungle in the south, are secondary vectors. P. falciparum is also suspected in the Central Selva. P. falciparum is especially dangerous because in many countries, including neighboring Brazil and Bolivia, this parasite has demonstrated resistance to chloroquine treatment and, furthermore, has proven fatal when attacking the central nervous system.

Malaria is debilitating in itself, and predisposes its victims to contracting other diseases, particularly tuberculosis, which is well-known as a cause of anemia. If malaria occurs together with other parasitic infections, like uncinariasis, which also produce anemia, the consequences can be more severe. Such is now the case in the Central Selva, in the Chanchamayo Valley, and in Perene.

Helminthiasis, caused by metazoan parasites, constitute another large group of parasitic diseases (Lumbreras, et al, 1977). Among these, Ascaris lumbricoides is widely distributed in Amazonia. It predominates in the Peruvian humid tropics, where it achieves greater size than in the mountains or along the coast, and in spite of the indiscriminate use of antiparasite medicine, it infects 40 to 60 percent.

Three other parasites, Ancylostoma duodenale, Necator americanus, and Strongyloides stercoralis are found almost exclusively in the humid tropics, with Necator americanus being the most common. In general terms, the prevalence indices of the uncinarias (Ancylostoma and Necator) can fluctuate from 15 percent to 70 percent, depending on the region and the sanitary conditions. People contaminated with uncinariasis eliminate eggs, which produce larvae. The eggs live in the warm, moist soil until they come into contact with and penetrate the skin of their host. When the parasite enters a blood vessel, it is transported to the lungs, where it passes through the walls of the alveoli. It next enters the respiratory tract and comes to the larynx, after which it passes to an upper section of the small intestine where it installs itself and grows. Attaching its "head" to the mucosa, the parasite begins to suck blood, causing anemia that becomes especially severe with massive infestations. Because of this, pallid children are frequently encountered in the tropics, with the rims of their eyes and the palms of their hands almost white. This anemia, combined with malabsorption, causes diarrhea and serious malnutrition. The condition is aggravated when it is combined with certain bacterial infections, which explains the frequency of bronchial and respiratory infections common in Amazonia.

The other parasite endemic to the humid tropics is Strongyloides stercoralis. The symptoms appear when larvae penetrate the skin and pass through the same cycle as the uncinarias, entering the lungs before eventually arriving in the digestive tract. The eggs are eliminated in the feces. Developing in warm and moist soil, some of them become filariform and wait to penetrate the skin of any person who comes into contact with them. Other larvae differentiate into free-living males and females; the females lay eggs and repeat the cycle, continuing the soil infestation of strongyloides larvae prolonging the possibility of infection. The prevalence of S. stercoralis in the Central Selva fluctuates between 16 and 40 percent (Lumbreras and Muñoz, 1963b).

Trichiuris trichiura, known as Trichocephalus dispar, is another cosmopolitan nematode that abounds in Amazonia. It imbeds in the lining of the large intestine, and absorbs nutrients. Because treatment of the parasite was difficult until recently, almost all people living in the jungle had it, with children in many cases exhibiting a special form called trichocephaliasic colitis.

For more than two decades, colonists have introduced Hymenolepis nana, a cestode parasite or platy-helminth worms that live in the intestines of man and higher animals. I n 1982, Lumbreras et al, found that 21.8 percent of 132 children given parasite examinations in La Merced contained H. nana. Infestation begins with the ingestion of mature eggs that contaminate food, some fruits and vegetables, and water. The parasite propagates easily in poor sanitary conditions.

Another relatively important parasite is Fasciola hepatica, which has been found in Tingo Maria. Veterinarians have detected it in livestock and have found the intermediate host, snails of the genus Limnea. It does not constitute a human problem at the moment, but improved control measures for livestock are needed to prevent its spread. Lumbreras et al, have found two cases of human paragonimiasis with associated lung damage, one from Tingo Maria, the other from Aucayacu. Human beings acquire them by eating the river crab, Pseudothelphusa chilensis which serves as the intermediate host. In Cajamarca and Libertad in the north Paragonimus mexicana (synonym: P. peruvianus) infests many, while human paragonimus in the Central Selva has not yet been identified, but P. inca and P. amazonicus have been found in certain animals.

Viral diseases

In the Peruvian jungle some viral diseases are native while others are imported. The latter include measles, which decimates non-immune native populations, poliomyelitis, parotiditis, and others which could be easily controlled with a massive vaccination program - if such an effort were possible. Viral infections indigenous to this region are less well understood, and thus more difficult to treat or eradicate.

Widespread in the tropics, yet still poorly understood in Peru, are the arboviroses. Serological investigations made in the high Central Selva region have confirmed the endemic existence of Mayaro virus (Buck et al, 1967), which belongs to arbovirosis group A. In endemic regions, the percentage of infection can fluctuate at between 10 and 50 percent of the population. The Mayaro virus is characterized by fever that is generally benign and of short duration. It has been isolated in mosquitoes, which transmit it, and in some wild vertebrates. Specific antibodies in the blood, produced by the virus' presence, have been isolated in monkeys, wild rodents, and oppossums, but in Peru itself antibodies have been found only in man.

In arbovirosis group B, Ilheus is endemic in the Amazon and especially prevalent in the low jungle. The agent of this arbovirosis has been isolated in mosquitoes of the genera Psorophora and Aedes, which seem to be the principal vectors, and in birds. It can also be inoculated into other animals, such as rats. Brazil, Trinidad, Colombia, Panama, Honduras, and Argentina all report the virus, but it has been confirmed in Peru only through the presence of antibodies in the blood serum. When present in man, it is probably clinically undetected in the majority of cases.

Dengue-2 is another Group B arbovirosis, although in Peru there have not been clinically demonstrated cases, nor has the virus been isolated. As with the majority of arboviroses, there is a high percentage of undetected infection. This virus has been isolated in domestic and wild birds, bats, and horses. In man, its occurrence is benign, with complete regression following a few days of fever and headache. However, in some exceptional cases, elderly patients exhibit serious symptoms of encephalitis and meningoencephalitis.

Finally, arbovirosis group B includes jungle or wild yellow fever, which is endemic in Peru (Lumbreras et al, 1982). It can be transmitted throughout the year, especially in December, January and February, because human migration into the jungle increases for agricultural purposes during these times. Important disease transmitters are mosquitoes of the genus Haemogogus, H. caricornii falco, Aedes and Sabethes. Yellow fever afflicts monkeys in the jungle, with the virus circulating among nocturnal howler monkeys (of the genus Alouatta, notably A. seniculus), squirrel monkey, (Saimiri sciureus), and the monkey genus Ateles of which A. belzebuth and paniscus are found in Peru. It is difficult to establish the frequency of infection, but many monkeys die. Some rodents and marsupials are also suspected of acting as reservoirs of the virus. The disease is prevalent in high forest 400-1000 meters above sea level, and most cases in Peru appear in Huanuco, Junin, San Martin, Madre de Dios, Ayacucho, Apurimac, and Puno. Recently, clinical cases have been recorded from the Yavari river near the Brazilian border, as well as other areas in Loreto. In man, yellow fever varies in its effects, from undetectably mild to fatal. It affects visitors to the interior of the jungle, with the time of incubation between the bite transmitting it and the appearance of the first symptoms between three and six days.

Vampire bats are the source of another important viral disease, a form of rabies (Rabia silvestre), which is restricted to Latin America (Acha and Szyfres, 1973). Of the bat species which carry the disease, Desmodes rotundus, Diphylla ecaudata, and Diaemus youngi. D. rotundus is important epidemiologically because of its wide distribution, from Mexico to central Argentina. This bat transmits bovine paralytic rabies, which is responsible for enormous cattle and livestock losses in many regions in tropical America. In cattle, the incubation period can be from 25 to 150 days, making detection and control difficult. Approximately 500,000 head are lost annually in Argentina, while in Peru, at the end of 1970 cattle mortality reached 40 percent of the total stock in a region near Pucallpa. Since 1929, when the first case of vampire bat-caused human rabies was observed, more than 170 cases have been recorded in Latin America.

Another viral problem in Amazonia is hepatitis A or endemic, infectious, or icteric epidemic hepatitis. Saguinus monkeys experimentally inoculated with active human serum can become infected, however, as can chimpanzees (McAler et al, 1975). Since electron microscopes have detected the virus in patients' feces, the probable route of infection is fecal oral. When viral hepatitis B has been detected in the jungle, it is suspected that insect bites are the cause.

Neither virus nor bacterium, the eye disease trachoma, characterized by granulomatous conjunctivitis, affects more than 500 million people. The infectious agent is Chlamydia tracginatus which has been found in different parts of Amazonia and its known reservoir is man, who spreads the infection through ocular secretions and possibly nasal mucous, or with objects contaminated with them. Its seriousness is aggravated by environmental conditions, such as dry winds, dust, fine sand, and the absence of water.

Diseases produced by Bacteria, Rickettsia, and Spirochaetes

Among bacterial diseases, tuberculosis, produced by Mycobacterium tuberculosis, is of primary importance in Amazonia, where malnutrition and the socioeconomic and hygienic conditions all encourage its presence. A person's predisposition to acquire respiratory infections originates with parasites which during their life cycles in a human body pass through capillaries to the alveoli, injuring the upper respiratory tract. This trauma is aggravated by malnutrition and parasitic anemia (Lumbreras, et al, 1967).

Another type of Mycobacterium, M. lepras, produces leprosy. This disease is found throughout the Ucayali watershed, in Amazonas, in parts of Huallaga, along some tributaries of the Marañon river, and in the highlands of Apurimac (Lumbreras et al, 1982). It becomes a mutilating disease when it is not diagnosed and treated; both the tuberculoid form and the lepromatose form affect the nerves, produces trophic disturbances and problems with sensation in the fingers and toes. The patient is also subject to mutilating accidents because of his inability to detect pain or heat.

The common staphylococcus bacterium produces serious infection in the humid tropics where conditions are favorable to its growth. In addition to common skin infections, infections like Piomiositis tropical, which was originally observed in Amazonia, can also be encountered. Produced by Estafilococo dorado in the majority of cases, the disease primarily affects the muscles in the thigh; thus, people who suffer from this infection characteristically cannot walk because of the intense pain.

Another health problem in Amazonia is Meningitis meningocosica. The disease is cyclic; after five years, it disappears, producing only occasional isolated cases.

Finally, the widespread availability of penicillin has reduced the threat of three historically important diseases: the flan, cuchipe. or raspberry, that is produced by Treponema pertenue; Mal de Pinto or white lion disease produced by Treponema herrejoni; and syphilis produced by Treponema pallidum. Flan was mentioned by Luis Pesce in 1908 and was widely distributed in Amazonia. Clinical cases have been observed very rarely in some high jungle regions, particularly Pozuzo. One penicillin injection is sufficient treatment. Mat de Pinto was found in numerous valleys on the Andes' western slope, the lower sections of the inter-Andean valleys of the Marañon and Huallaga rivers, and upper reaches of Amazonian tributaries. This disease is known in the jungle as mange and, other parts, as leprosy. It produces a series of scaly and whitened lesions (caused by witchcraft, some believe) generally localized on the face, legs, and soles of the feet where they are called llaga. Penicillin has virtually wiped out this disease, as it has helped to control the spread of syphilis.

Recent studies of human and animal leptospirosis have been carried out in different regions of the country finding a high percentage of human infection in the central tropics. In the Central Selva, Liceras de Hidalgo (1981) demonstrated serological infection in 9 of 15 marsupials of the species Philander opossum, and, more importantly, the presence of leptospiras in 11 of 15 different animals. The same author also demonstrated that 3 of 15 Didelphis marsupialis possessed antibodies; he also found mild serological infections in a squirrel (Sciurus sp.), a rabbit (Silvilagus sp.), and an iguana (Tupinambis nigropunctalus).

Mycotic diseases

In the Amazonian jungle superficial fungi called dermatophytes produce a series of diseases which affect the skin, hair, and nails (Burstein, 1968). Other types of skin lesions are caused by other dermatophytes, such as T. rubrum, T. mentagrophytes, and others. In the humid tropics, forms of superficial mycosis that attack hairy skin can be found relatively frequently, especially on the heads of children.

Among the most important mycoses that can be acquired in the humid tropics are the fungus diseases acquired through the respiratory tract that can extend to different organs and systems of the body. Two of them are paracoccidiodomycosis, also known as South American blastomycosis, and histoplasmosis. Known in Peru as Tingo Maria fever (Zuñiga, 1970), histoplasmosis was first observed in people visiting Las Lechuzas caves located in Tingo Maria where the fungus grows in the feces of the abundant oilbirds (Steatornis caripensis). In endemic regions like the Central Selva as many as 100 percent of people tested for the fungus were found to have it, but those who actually get sick or die are few. The rare fatal cases are apparently due either to damage to the host's immunity, or to the virulence of the infecting strain.

Lobomycosis or Blastomycosis queloidiana has also been diagnosed in the Peruvian jungle. This is caused by the fungus Loboa toboi, which has numerous other names such as Glenosporella loboi, Blastomyces loboi, Glenosporopsis amazonica, and Paracoccidiodes loboi. This mycosis only affects the skin.

Another systemic or generalized mycosis that can be found more frequently in the humid tropics is Maduro-mycosis, known also as wooden foot. It is caused by many agents, the principal one being Madurella mycetomi. This mycosis is characterized by a marked deformation in the feet.

Finally, some systemic mycoses are not restricted to the humid tropics. One of these is cryptococcosis which is produced by Cryptococcus neoformans. Although it enters the body via the respiratory tract, it causes serious damage to the central nervous system, and death if it is not treated

Fauna harmful to man

Common in Amazonia is the nigua, Tunga penetrans. The fecund female of this small flea usually enters the skin of the foot (though other parts of the body are also susceptible) where her abdomen becomes distended from ingested blood and from growing eggs. The consequences to the host can be itching, inflammation, and secondary infection, which can be especially dangerous when the infection is tetanus, caused by Closiridium tetani.

Izango, Japa inacue, or isangue is produced by a trombicula. This tiny red organism, one millimeter long, generally attacks uncovered parts of the leg and produces an intense itching that requires continued scratching.

Acarosis, known commonly as mundialito or mange, comes from a mite, Sarcoptes scabiei, that penetrates the skin and produces itching between the fingers and toes, on the wrists, the waist, the groin and genitals, under the breasts of women, and near the armpits. Infections from mites other than Sarcoptes also cause cutaneous itching; they sometimes are found in straw mattresses and are not necessarily attached to the skin.

Other infestations are caused by fly larvae. They can be biontophages, which feed on living tissue at some stage in their life cycle, or necrobiontophages, which must feed on the dead tissue of living animals. Among the biontophages of the humid tropics is Dermtobia hominis, a large fly with a brilliant green abdomen that hunts in full flight a hematophage insect, possibly a Culex mosquito or the stable fly Stomoxis calcitrana, and deposits on their abdomens eggs that are held in place by a gummy substance. When the hematophage insect bites a human victim the eggs are left on the skin. The larvae rapidly hatch, and one enters the skin through the insect bite. This larva implants itself under the skin in subcutaneous tissue and grows slowly. The condition is also known as myasis forunculosa and, in the jungle, as suturo, suchllacurro, pacacuro, and gusano de monte, among others. Natives have methods of treating it.

Other myasis found along the coast, in the mountains, and in the jungle are those produced by the biontophage fly Cochlyomyia hominivorax. In contrast to Dermatobia the female deposits a large number of eggs along the edge of cutaneous lesions and, after a short time the larvae hatch and voraciously enter the open lesions (Lumbreras and Polack, 1955). It is quite possible that other myasis exist in the region. These can include the cosmopolitan urinarias Fannia carricularis and Oostras ovis that produce ocular myasis in man and are found where livestock, particularly sheep, are raised. Cases have also been recorded in the humid tropics of caterpillar dermatitis, cutaneous reactions caused by irritating substances found in the hairs of butterfly and moth caterpillars. These lesions are transitory and not serious. Wasp and bee bites occasionally cause problems with people sensitive to them.

Spider bites do not seem to be particularly harmful in the humid tropics. Only spiders of the genus Ctenus are considered potentially dangerous, but cases of human illness from them have not been reported from hospitals or health centers.

Snakes on the other hand do cause trouble for people and animals. Of the genus Bothrops the most frequent is G. atrox, which is widely distributed and which causes 70 percent of the incidents in the jungle (Pesce and Lumbreras, 1957; Meneses, 1974a, b). It is followed by B. bilineatus, known also as loromachaco, an arboreal snake found throughout Amazonia. B. castelnaudi, known as the jergon de arbol, is also widely distributed in Amazonia, as is B. microphthalmus, the jergon pudridora and G. cloremelas or lamon, an arboreal snake found in the Oxapampa region, among others. Serpents of the Bothrops genus can cause cutaneous necrosis, severe pain, swelling, and vesicle formation. Sixteen species of snakes of the family Elapidas are distributed throughout the jungle; they are known as coral, naca naca, chaquira, and coralillo. Finally, widespread in the jungle is the serpent Lachesis muta (Vellard, 1948; Kostritsky, 1971), commonly known as the schuschupe. Its bite causes intense pain in the bitten area, visual problems, and cutaneous necrosis. In the majority of cases the bite proves fatal in a few hours. The bite of Lachesis muta may be rare, but it also may be that cases are not reported because those bitten die in deep forest.

Consideration of animal hazards in Amazonian rivers can begin with the canero (Vandellia cirrhosa), a fish of the family Pygidudae, which grows to 20 cm. in length. It is carnivorous, aggressively and rapidly attacking man and animals and producing a lesion from which it sucks blood. The Chuccha-canero, which includes Vandellia plazaii, V. cirrhosa, and Urinophilus diabolicus, is so called because it resembles a piece of hair, measuring 8 cm. long and 0.5 cm. wide. It enters the urethras and other natural openings of men and women, causing intense pain and serious hermorrhaging.

Three species of fish known throughout the world also cause trouble in Amazonian rivers (Sánchez, 1951). The first is of the genus Serrasalmus, S. rhombeus, and S. natteri, commonly known as piranhas. With their sharp teeth, they tear out chunks of flesh and, as they generally attack in numbers, they can kill humans. Another dangerous fish is the ray, Potamotrigon hystrix. It forms large colonies during seasons of low water when they appear on sandy bottoms. Their camouflage makes them difficult to distinguish, and they react violently when stepped on, causing painful wounds with two spines in their tails. Finally, in the swamps and lakes of Amazonia the electric eel, Electrophorus electricus is found. This fish produces electric discharges capable of killing lower animals and of knocking men senseless, sometimes resulting in drowning.

Medicinal plants

Floral resources are widely employed in Peru, especially in the jungle. They are used directly as medicine and indirectly in the treatment of psychological diseases, usually in rituals (Chirif, 1978; Ortega, 1979). An infinite variety of plants and tree resins exists. Many have been studied scientifically, their active ingredients obtained, and their pharmacological effects proven. Many others, however, are still used empirically.

Cinchona officinalis, known as cascarilla, C. calisaya, C. calisaya del monte, C. c. del pajonal, and quina-quina, is a species of major importance because its bark yields the quinine that was the first treatment for malaria. Known since the 16th century, quinine's use has diminished in recent times due to the development of other chemotherapeutic products, but it is now coming back into use because some plasmodia, among them P. falciparum, have developed a resistance to chloroquine.

Ficus anthetmintica, known as hoje, oje, and huito, is a tree, the bark of which produces a milky resin that acts very effectively as a purgative and a vermifuge to kill intestinal worms. It is exported as a powder and can be administered in capsules. Another species, Ficus cariica, or higo, produces dry fruit, which, softened in water, is used to wash and rub out freckles. The latex of the green fruit is also used to cauterize callouses, while, heated, the dried fig is employed to treat inguinal adenitis, and the water in which dried figs have been steeped, with salt and vinegar added, is used to combat dandruff. F. glabrata, known as pitongo by the Machinguenga Indians, is used as a purgative by rubber workers. F. killipii, called chimico negro or renaco Colorado, is used as a remedy for sterility in women.

Peperonia rubea, or lancetilla del monte, is mixed with beaten eggs and used to combat colds and bronchitis. P. inaequalifolia or congona is applied to cases of gingivitis and otitis with good results. Chlorophora tinctoria, a tree known as insira and limulana, produces a bitter-tasting and ill-smelling bark that is used as a tonic and astringent and, in large doses, as a purgative. Ashes made from its wood are recommended in the treatment of gout and rheumatism, and its astringent fruit is gargled to treat mouth problems and sore throats. Its root is used as a diuretic, while its bark resin is used by some indigenous tribes painlessly to extract the roots of molars.

Genipa americana, known as huito, isso, jagua, mandi, palo Colorado, and yaco-huito, has a fruit rich in tannin. When fermented, it produces a liquor called guacamote and an indelible ink used to dye hair black. When green, the fruit is wrapped in banana leaves, toasted over a slow fire, and applied to the skin. The skin turns black and repels mosquitoes for eight days, after which it becomes clean and free of side-effects. The seeds can also be used as a rapid and vigorous emetic.

Psidium guayava, known as guayaba and jagua, has agreeably-tasting fruit. The tender leaves of the shoot are chewed and then squeezed until drops appear. The treatment is used for severe conjunctivitis and dysentery. Furthermore, the leaves and root are astringent, and the boiled bark is used to combat stomachache.

Hura crepitans, commonly called hura and catahua, is a large jungle tree, the bark of which is chemically similar to curare and thus very caustic and poisonous. If chips of its wood come into contact with the conjunctiva, its caustic effects can cause blindness. Its seeds are utilized to provoke vomiting and as a purgative, in some cases causing dysentery. An oil is extracted from the fruit for use in lamps, and cigars made from the leaves can be used to combat asthma.

An infusion made from the bark of Paullina yoco, commonly called yoco, yoco blanco, and huarmiyoco, is employed as a stimulant to combat hunger and fatigue. The soft tissue is scraped off and squeezed until juice containing caffeine is obtained and added to cold water. The beverage creates a prickling sensation in the fingers and a sensation of well-being.

Theobromoa cacao, known as cacao, cacahuillo, canga, ccarhua, kimituhi by the Campa Indians, and turanqui by the Shipibo Indians, is used as a medicine for convulsive cough, while the boiled husks are used for dysentery. The dense chocolate is applied to bronchial diseases, taken as a galactophore when mixed with powdered rice and cinnamon, and used as a poultice for pulmonary problems when combined with egg yolk, grease, and sulfur.

Erythrina poeppigiana, known as amashisa and oropel, is a tree with bark that produces a resin used for contusions and swellings. It has been found to contain various medically-important alkaloids.

Fifty-five of the 700 species belonging to the genus Cyperus in Peru are known in the jungle as piri-piri.They are very effective when used for snakebite; the bulb of the plant is chewed, the sap swallowed, and the remaining material is applied directly to the bite and the area around it.

Chenopodium ambrosioides, known as paico, amush, camatai, and cashiva, has been used since 1906 in many ways; when boiled, it is used as a vermifuge, as an abdominal colic, and for the treatment of hemorrhoids. Its oil is used to combat parasites. It has been demonstrated that chenopodium oil can eliminate 70-90 percent of ascaris infestations; unfortunately it is so toxic it sometimes proves fatal.

The leaves of the tree, Meca parviflora, known as yanamuco, are chewed, initially coloring the teeth black, but then leaving them clean and white with their enamel intact after a few days. Abuta grandiflora, or caimitillo, sananga, and trompepero sanango, is a shrub, small tree, or vine, the root of which is used as a remedy for anemia and colds.

Jatropa curcas, known as pinon or pinol, is a euphorb that produces seeds used as a purgative (just one seed is effective for adults) while the plant's leaves are used to heal cutaneous abscesses. J. gossypifolia produces seeds with abundant oil and with purgative and emetic properties. Furthermore, its latex treats burns and alleviates hemorrhoidal inflammation, while its leaves are used as poultices for swellings.

A large number of species belonging to the Piperaceae family are referred to as cordoncillo, matico, mocco-mocco, and yerba del soldado. Of these, Piper elongatum is used as a powder to heal ulcers by encouraging the growth of scar tissue, while as an infusion it is employed to treat wounds. The euphorb, Euphorbia cotinoides, or huarus, juquilla, or yuquillo, is widely employed to cure conjunctivitis or mal de ojos.

Voucapoua americana, a legume known as huacapu, produces an oil that acts as a purgative, and its bark brings about abortion. Allcuchuchu, meaning dog nipple, is a plant that sprouts red flowers with white corolla centers that are always filled with water. Peasants believe that if the water is collected before dawn, and applied to the breast it will enable women to produce milk even though they are old or have never had children.

Seventy-one species of Passiflora exist in Peru, commonly known as tumbo. P. mixta and P. mollissima are found in the jungle. Their fruits are eaten and used to eliminate kidney stones, while their leaves are used as vermifuges and to induce abortions. Syrup made from their roots is used to treat pneumonia.

The mint Melissa officinalis is called abeja (bee), because it is attractive to this insect, and toronjil. An infusion of this plant is an antispasmodic, either alone or mixed with orange rinds. Boiled, it is employed as a sedative, to treat stomachache, and to help in childbirth.

The leaf sap and boiled roots of Scoparia dulcis, known as escobilla, escobilla del Peru, nucnu pichana or piqui-pichana, are used as astringents and as antipyretics to combat fever. Jacaranda copaia, or amchi-ponga, aspingo, chichara caspi, ishpingo, ishtapi, para-visco, and soliman de monte is reported as having been used to treat syphillis, and its flowers have proven effective in treating dysentery. Also used for dysentery is the bark of the tree Byrsonima coriacea, called indano, indano Colorado, chanchi, and quillo sisa. Powder made from the plant is also used to cauterize bleeding wounds.

Pseudocalymma alliaceum, known commonly as sucho-ajo and ajo sacha, is a shrub used for pain, kidney diseases, and as a poultice.

A red resin is obtained from the sangre de drago or sangre de grado, Croton salutaris and C. palonastigma, by making incisions in the bark; it has powerful astringent and hemostatic effects. Pulverized and placed in a container of boiled plantain, it is used to stop hemorrhaging of organs and wounds. It is also used for the treatment of gastric and duodenal ulcers and to cauterize skin lesions. A piece of this gamoresin in the mouth holds loose teeth, while powder obtained from the tree is effective in the treatment of hemorrhoids and rectal prolapse.

Condaminea corymbosa, belonging to the Rubiaceae family, is called sauco or ccaratu and is often used mixed with cinchona. Another plant, also known as sauco, as well as ccola, kyola, ram rash, and yalan, produces flowers which, when boiled, are employed as sudorifics and are widely used to combat smallpox. A boiled mixture of sauco and chamomille, lavender, and cows-milk is applied to bladder and prostate irritation. It is also felt that the leaf poultices, plasters made from soap, and juice from the flowers all favor suppuration and thus reduce inflammation of inflamed ganglia and adenomegalias. Also, boiled, the plant is used to bathe cheeks to combat toothache, while a medicinal mouth-wash made from the boiled fruit is applied to relieve stomach problems.

Numerous species of legumes of the genus Cassia are used for various purposes. C. alata effectively treats certain skin problems especially herpes infections, while a strong concoction kills piques, niguas, or Tunga penetrans. In India, it is utilized for all types of venomous bites, and juice extracted from the leaves and mixed with lemon juice is used to cure rashes.

C. bicapsularis, known as alcaparillo and alcapaquilla is used as a purgative, although in some cases it can produce colic. Another species, C. cuspidata, was introduced to the country during the conquest. Its mucillaginous pulp is considered to be a laxative.

The llanten, llantai, or llantin macho, is a cultivated plant. A concoction made from it is used as an astringent for cleaning wounds. Its whole leaves, fried in olive oil, are effective analgesics for eye pain. Known scientifically as Plantago mayor, the leaves, either macerated or in an infusion, are also applied as an enema to cases of dysentery. Combined with barley, marshmallow, purslane, and ivy, it is used to treat hemoptysis (hemorrhaging of the lung lining that leads to blood expectoration). A concoction made from the plant's leaves, rosemary, and egg white is also used to control hematemesis (vomiting of blood arising from lesions of the mucosa of the digestive tract).

Annona cherimelia, chirimoyo, or chirimoya, is native to the Peru-Ecuador border, and its lightly roasted leaves are applied to the temple to relieve headache. A concoction made from the root is used for dysentery, and it is thought that the powdered seeds can kill lice. For obstructions of the biliary ducts and the digestive tract, Hidrocotyle umbelata, or oreja de abad, mantejillo, mateollo, or mattecllu; is often employed. It can also serve as an aperient and diuretic, while large doses are used as an emetic.

Often plants are used in rituals that may also have therapeutic properties. One of these, Banisteriopsis caapi, or ayahuasca, soga de muerto, ayawasca, capi, yaque or punga huasca has been reserved for sacred rites throughout the northeast of Peru up to Ecuador, Colombia, Venezuela, and northeastern Brazil. Small doses produce euphoria, while larger doses produce dreams rich in images, color, and clarity, and a wide range of hallucinations. In the last stage the user falls into a deep sleep, losing almost all sensibility. Ayahuasca is used as a medicine, an aphrodisiac, and for divination. Benisterine is the plant's active alkaloid.

Some of the medical claims made for these plants have been scientifically observed; others require study. Accounts of the healing effects of plants, resins, seeds, fruits, roots, are abundant among the people of Amazonia, but this information needs to be collected and confirmed as much as possible through careful examination. Perhaps the solution to many of the health problems encountered by man in the humid tropics may lie in the careful and conscientious use of the naturally-healing substances that are already there.


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