Short report: extended follow-up of the natural history of persons infected with Leishmania chagasi.

A five-year follow-up of the natural history of 924 children exposed to or infected with Leishmania chagasi was conducted in a rural area of northeast Brazil. Seventy-eight percent of the children sought were located. There was no evidence of smoldering disease or long subclinical latency in this population. The overall prevalence of clinical visceral leishmaniasis in this population was 6.1%, with a mortality rate of 10%.

Bubonic leishmaniasis: a common manifestation of Leishmania (Viannia) braziliensis infection in Ceara, Brazil.

Enlarged regional lymph nodes have been reported to accompany the cutaneous lesions of Leishmania (Viannia) braziliensis (= L. braziliensis). A survey in Ceara State, Brazil indicated that 77% of persons (456 of 595) with parasitologically confirmed cutaneous leishmaniasis reported lymphadenopathy in addition to skin lesions. A group of 169 persons with recently diagnosed leishmaniasis and lymph nodes measuring > or = 2 cm in diameter (mean = 3.6 cm, maximum = 10.5 cm) underwent detailed clinical examination. Lymphadenopathy preceded the skin lesions in more than two-thirds of these, on the average by two weeks. Cultures of lymph node aspirates yielded Leishmania more frequently (86%) than cultures of aspirates of skin (53%) or biopsies of skin (74%). Parasites were isolated from the peripheral blood of one patient. Persons with lymphadenopathy gave a history of fever and had enlarged livers or spleens more often than a comparison group of 50 persons with cutaneous lesions but no lymphadenopathy. Persons with lymphadenopathy had more intense leishmanin skin reactions and lymphocyte proliferation following stimulation with specific antigens, whereas persons without lymphadenopathy had a higher frequency of previous infection. Isolates of parasites from both groups were identified as L. braziliensis. These data demonstrate the early spread of L. braziliensis beyond the skin and suggest differences in host immunity between persons with and without lymphadenopathy. Leishmaniasis braziliensis should be considered in cases of unexplained lymphadenopathy in endemic areas.

Cryptosporidial and microsporidial infections in human immunodeficiency virus-infected patients in northeastern Brazil.

To determine the frequency of the parasitic pathogens in human immunodeficiency virus (HIV)-infected patients in a developing world setting, 295 stool specimens were examined from 166 HIV-positive patients (49% with AIDS) at São José Hospital, Fortaleza, Brazil, from September 1990 to March 1992. Significantly more patients with diarrhea (85%) than without (66%) had AIDS or AIDS-related complex (ARC) (P < .005). Of the potential parasitic causes of diarrhea, only Cryptosporidium parvum and microsporidia were significantly associated with diarrheal disease. Infections with C. parvum, but not microsporidia, were associated with the rainy season (P < .005). Thus, C. parvum and microsporidia are the most common intestinal parasites associated with diarrhea in an HIV-infected population in Brazil and are associated with advanced HIV disease. The association of C. parvum infections with the rainy season suggests that contaminated water may be important in its transmission; however, the source of human microsporidia requires further investigation.

[Analysis of the monthly incidence of cutaneous leishmaniasis in Ceará (Brazil) between 1986 and 1990]. / Analyse de l'incidence mensuelle de la leishmaniose tégumentaire dans le Ceará (Brésil) entre 1986 et 1990.

To determine the value of an epidemiological surveillance system, we evaluated the incidence rate and trends of American Cutaneous Leishmaniasis (ACL) in three health districts of Ceara state, Brazil. We used a retrospective time series analysis of ACL notifications in Ceara state between 1986 and 1990. The trend of this endemic/epidemic disease was analysed by using three types of modeling on the moving average graph: a linear, linear periodic and non linear periodic model. The study samples consisted of the 14,615 cases of ACL notified in Ceara state between 1986 and 1990. Males accounted for 54% of cases. Age was between 1 month and 19 years in 42% of cases. Most cases (81%) were diagnosed on clinical grounds only. After calculation of the moving average and application of a linear regression model to these means, the trend analysis revealed that 1) there was a significant trend towards an increase in two of the three health districts, with correlation coefficients of 0.31 and 0.49 (Student's t test = 2.24 and 3.88) and a significant trend towards a decrease in the remaining district (correlation coefficient = 0.51, t = 4.1). The linear periodic model showed a cyclic representation with a 36-month period and a base of 241. The non linear periodic model showed a cycle of 32 months and a base of 241, and was a better representation of the disease variations. Despite the limited study period, it appears that the 32-month cycle could be attributed to meteorological conditions. Field studies are underway to determine the precise causes of this periodicity.

Correlates of Leishmania-specific immunity in the clinical spectrum of infection with Leishmania chagasi.

Patients from across the spectrum of clinical manifestations of Leishmania chagasi infection were evaluated for in vitro correlates of immunity. Peripheral blood mononuclear cells were assayed for parasite-specific lymphoproliferation, cytokine generation, and the capacity to activate autologous macrophages to kill intracellular amastigotes. Patients with acute kala-azar were generally unreactive in each of these assays. Children with subclinical infection demonstrated relatively low levels of proliferation and interferon-gamma production, but none went on to develop overt kala-azar during the study. Patients evaluated after therapy for kala-azar demonstrated yet higher levels of lymphoproliferation and cytokine generation and produced low but significant levels of cytokines in vitro in response to parasite antigens, but not during the activation of infected macrophages. Finally, peripheral blood mononuclear cells from adults with positive delayed-type hypersensitivity responses and no history of kala-azar showed the broadest reactivity in vitro. These patients' cells generated the largest amounts of activating cytokines in vitro during the activation of autologous macrophages to a leishmanicidal state.

[Cutaneous parasitism by Leishmania (Leishmania) chagasi during South American visceral leishmaniasis]. / Parasitisme cutané par Leishmania (Leishmania) chagasi au cours de la leishmaniose viscérale sud-américaine.

Eighteen patients from the northeastern Brazilian State of Ceara with proven kala-azar were studied for evidence of skin parasitism: two had ulcerative or papular skin lesions and 16 had clinically normal skin. Punch biopsies (3 mm) of intact paraspinal subscapular skin were performed on all patients; in those with papular or ulcerative lesions biopsies also were taken from an active site. One of each of the subscapsular biopsies and half of each biopsy from an active lesion were studied; the other specimens were seeded on NNN Difco Blood Agar Base Medium for parasite culture. The biopsies revealed a discrete to intense mononuclear inflammatory infiltrate, predominantly perivascular in nature. No amastigotes were observed in any tissue sections but 7 of the 18 patients yielded promastigotes on skin culture identified by monoclonal antibodies and by enzyme electrophoresis as Leishmania (Leishmania) chagasi [L. (L.) chagasi]. The isolation of Leishmania (Leishmania) chagasi, the recognized aetiologic agent of visceral leishmaniasis in the New World, from the skin of nearly 40% of 18 AVL patients proves dermatotropism of L. (L.) chagasi occurs and may be frequent in neotropical human visceral leishmaniasis (AVL.). Infected persons with skin parasites could act as a reservoir of infection and allow human to human transmission.