Availability of HIV care in Central America.

Central America is an area with a growing human immunodeficiency virus (HIV) epidemic, but with marked limitations in its health care infrastructure. Estimated adult HIV infection rates range from 0.20% in Nicaragua to 2.01% in Belize. Hospitals and clinicians with experience in HIV care exist mainly, if not only, in capital cities and principal economic centers. Nationally sponsored social security systems in each country consistently offer a wider range of services than do ministry of health systems. Estimated access to the social security system ranges from 0% in Belize and 10% of the population in Honduras to 95% in Costa Rica. Combination antiretroviral therapy is not available through the ministries of health and zidovudine is only sporadically available for prevention of perinatal transmission. Combination therapy is available through the social security system in the countries of Guatemala, Panama, and Costa Rica only. A wide variety of antiretroviral agents are available through private pharmacies in all countries except Belize. With the exception of Costa Ricans, most people with HIV infection in Central America have limited access to HIV-specific health services and limited or no access to antiretroviral agents.

Vertebrate hosts and vectors of Trypanosoma rangeli in the Amazon Basin of Brazil.

A total of 46 Trypanosoma rangeli stocks were isolated from naturally infected mammals and triatomine vectors. Twenty-two stocks were from the common opossum (Didelphis marsupialis), one from the brown "4-eyed" opossum (Metachirus nudicaudatus), one from the anteater (Tamandua tetradactyla), one from the coati (Nasua nasua), seven from Rhodnius pictipes and 14 from Rhodnius robustus. Two stocks were also isolated from recently fed sandflies (Lutzomyia sp., Shannoni group). The stocks were identified as T. rangeli on the basis of natural or experimental salivary gland infections in Rhodnius, inoculative (anterior station) transmission to mice, morphological parameters in parasitemic mice and comparisons of isozyme profiles with a known stock of T. rangeli isolated from man. Three other trypanosome stocks from D. marsupialis, T. tetradactyla and the three-toed sloth (Bradypus tridactylus) were morphologically similar to T. rangeli in culture but had quite different isozyme profiles and were not identified. It is concluded that T. rangeli is widely distributed in Amazonas, Pará and Rondonia States of Brazil, and probably extends into other regions where R. pictipes and R. robustus are known to occur. R. pictipes is light-attracted into houses and occasionally transmits Chagas' disease to man. It is likely that T. rangeli is also occasionally transmitted to man in the Amazon basin.

El xenodiagnostico artificial en la enfermedad de Chagas. / Artificial xenodiagnosis in Chagas' disease

Se estudia una nueva tecnica de xenodiagnostico artificial, comparando la efectividad de diversos tipos de membranas y de anticoagulantes para favorecer la alimentacion, a temperatura ambiente, de ninfas de Rhodnius prolixus

Do radically dissimilar Trypanosoma cruzi strains (zymodemes) cause Venezuelan and Brazilian forms of Chagas' disease?

316 isolates of Trypanosoma cruzi, the causative organism of Chagas' disease, were collected from three geographical areas: Venezuela, where Chagas' disease does not cause megacardia, megaoesophagus, and megacolon; the Brazilian Amazon basin, where T. cruzi is silvatic and human infection is rare; and central and eastern Brazil, where T. cruzi infection is commonly associated with "mega" syndromes. The distribution in these regions of three radically dissimilar enzymic strains or "zymodemes" of T. cruzi (Z1, Z2, and Z3) was compared. Endemic Chagas' disease in Venezuela ws predominantly due to T. cruzi Z1 and rarely to T. cruzi Z3. T. cruzi Z1 and Z3 also caused the sporadic cases of Chagas' disease in the Brazilian Amazon basin. A quite distinct T. cruzi zymodeme, Z2, not found in either Venezuela or the Amazon basin, was isolated from the vast majority of patients in central and eastern Brazil. These observations suggest that different aetiological agents might account for the difference between the Venezuelan and Brazilian forms of Chagas' disease.

Field evaluation of primaquine in the control of Plasmodium vivax.

Two regimens of primaquine in combination with amodiaquine have been compared with amodiaquine alone in known cases of Plasmodium vivax in an endemic area of El Salvador, C.A. A 5-day regimen of primaquine, with dosages based on an adult dose of 15 mg per day, produced a substantial reduction in the numbers of patients experiencing renewed parasite activity and in the number of parasitemias experienced by the group during 9 mo of posttreatment observation, when compared with patients treated only with amodiaquine. A single dose regimen, based on an adult dose of 45 mg, similarly reduced the number of patients with renewed parasite activity and the number of parasitemias in the group. Those patients who experienced malaria attacks subsequent to treatment with either primaquine regimen experienced fewer such attacks than did those receiving amodiaquine alone. It is concluded that such primaquine regimens, which are more practicable for field use than the full 14-days curative regimen, are of value to both the patient and the community through the reduction of parasite episodes and the reduction of the source of mosquito infection for continuation of transmission.

Domestic triatomines (Reduviidae) and insect trypanosome infections in El Salvador, C.A.

Twenty-five Salvadoran communities have been surveyed to learn more about the distribution of Chagas' disease vectors and trypanosome parasites in that country. The results indicate that each of several factors--local variations in housing construction, insecticide applications, geographic elevation, and the vector species involved--can have a critical effect on transmission of the disease agent.

The seroepidemiology of malaria in Middle America. IV. Passage of malaria antibodies from mothers to infants.

In an area of El Salvador moderately endemic for malaria, use of the indirect fluorescent antibody test (IFA) showed that 44% of the infants born to mothers who had IFA responses to Plasmodium vivax of 1:20 or higher during the latter part of their pregnancy had positive IFA responses of 1:10 or higher to this antigen. No serum from an infant was positive in the absence of some level of malarial response in the mother.

Variations in disease prevalence in the Americas.

Data are presented from North American and Latin American countries of the leading causes of death and death rates, demonstrating the sharp differences based on social and economic development of these respective countries. Whereas ischemic heart disease and malignant neoplasms head the list of deaths in the United States and Canada, infective and parasitic diseases of the gut, with diarrhea very common, are the principal causes of death in Latin America. Nutritional deficiency, the most important contributory cause associated with infections and diarrhea, accounts for the very high infant mortality rate in the latter countries. These pathologic conditions have a direct relationship to the degree of social and economic level of development in Latin America, and constitute a complex public health problem of enormous proportions.

Chagas' disease in El Salvador.

Several studies on Chagas' disease in El Salvador have supplied important epidemiologic information, including the following: (1) Rates of house infestation by triatomid vectors have ranged from 26.3 per cent to 100 per cent in various localities studied, higher rates being found in rural than in urban areas. (2) Triatoma dimidiata and Rhodnius prolixus are the two vectors of T. cruzi in El Salvador, with T. dimidiata predominating in localities at elevations above 600 meters and R. prolixus in those below 300 meters. (3) T. cruzi infection rates in these triatomids have ranged from 15.3 to 48.8 per cent, the average being 25.3 per cent. The average rate found for T. rangeli infection of these triatomids was 5.6 per cent. (4) T. cruzi infection in humans has been nore prevalent among rural dwellers than among urban inhibitants. Xenodiagnosis positivity rates have ranged between 3.8 and 18.4 per cent of the individuals examined. Positive reactions to the complement fixation test have ranged from 17.3 to 46.7 per cent. (5) The acute phase of the disease has been observed in both children and young adults. Nevertheless, ECG and radiologic changes appear to be less common and milder than those reported in South American countries. (6) Further studies are required in order to better define the status of Chagas' disease in El Salvador.