Human strongyloidiasis is an important health problem in the southeast region of Peruvian Amazon, due to its prevalence and long term morbidity. An epidemiological study was conducted in the Peruvian Amazon area of Puerto Maldonado to determine the prevalence of strongyloidiasis in the population. Stool samples were collected from 1,133 patients at the outpatient department of our clinic. Strongyloidiasis affected 221 examined patients (20%). Prevalence was highest in males, mostly in children and elderly men. People living in urban and marginal urban areas, those coming from outside the region, and Andean people, showed the highest prevalences. Pre-school children were more likely to be parasitized than older children. The most common symptoms were diarrhea (55%), abdominal pain (32%) and cough (53%). One in 7 (13%) affected patients presented with moderate or severe symptoms, including life-threatening complications. Other intestinal parasites were found frequently in patients diagnosed with strongyloidiasis. Improved human waste disposal services are considered to be the main requirement to reduce the high prevalence of this disease.

A Colombian strain of Trypanosoma rangeli was characterized by analyzing its behaviour in different axenic and cellular culture, its infection rate and the histopathological lesions produced in experimental animals. Although slight inflammatory infiltrations were shown in different histopathological sections, no pseudocysts could be observed. Grace's insect medium is better than liver infusion tryptose or artificial triatomine urine supplemented with proline when studying T. rangeli metacyclogenesis, with a peak of 32% trypomastigotes. High infection rates were found in VERO and J774 cells. Because of its 100% infectivity rates and adequacy of parasitemia levels, C23 strain is a suitable model of T. rangeli biology study

After isolating three clones of Trypanasoma cruzi (Bolivia), we first characterized them according to parasitaemia, pleomorphism and virulence, and then histopathologically. The study's interest lies on the hypothesis that clonal evolution of T. cruzi has a major impact on biologically relevant properties of this parasite. Data obtained from the studies of parasitaemia, pleomorphism and virulence showed no differences between the groups studied. As a final point, the histopathological study shows us a muscular tissue tropism both in clones and in their mother strain (Bolivia). In this paper, we conclude that Bolivia strain and clones isolated from it, pertaining to the same major clone share similar biological properties.