Seasonal trends of Cyclospora cayetanensis infections in a community of Falcon State, Northwestern Venezuela

BACKGROUND

Cyclosporiasis has a marked seasonality. Few community-based studies have addressed this issue and there are no reports from Venezuela. A study was conducted to determine the seasonal variation of infection in a community from Falcon State, Venezuela.

METHODS

A sample of 732 individuals was collected for 1 y. Stools were examined with modified Ziehl-Neelsen carbolfuchsin staining of ethyl acetate-formalin concentrates and ultraviolet epiflorescence of wet mounts.

RESULTS

Cyclospora prevalence was 9.9% (73/732) with monthly variation from 0% to 35.3%. A trend of increased infections coinciding with the rainy time was observed (p<0.001).

CONCLUSIONS

Cyclosporiasis is common in this area with high endemicity during the rainy periods.

Seroepidemiology of toxoplasmosis in amerindians from western Venezuela

A survey of 447 Amerindians aged 1-69 years (mean age, 18.6 +/- 15.8 years) in 3 mountain and 1 lowland communities from Venezuela were studied to determine the seroprevalence of Toxoplasma gondii, the environmental risk factors for the infection, and how the process of acculturation may affect the transmission rate. Serum samples were tested for immunoglobulin G antibodies by a commercial indirect hemagglutination test. The overall prevalence of infection was 49.7% (222 of 447) and ranged 38.2-62.4%. A higher antibody rate was found in the lowland setting as compared with those from the mountain area (P < 0.001). The geometric mean titer in the overall population was 280.3. No age-antibody association was detected in the mountain communities, although a gradual increase in positivity with increasing age (P < 0.01) was observed in the lowland setting, reaching a peak of 83.3% in the oldest group. The results suggest that transmission by infective cat feces may play a predominant role in the spread of infection in this population. This study demonstrates the environmental Toxoplasma infection pressure in this sylvatic population and how transmission rate is facilitated by environmental changes produced by acculturation.

Cryptosporidium parvum in children with diarrhea in Zulia State, Venezuela

The prevalence and importance of Cryptosporidium parvum as a causal agent of acute diarrhea among pediatric patients from Zulia State, Venezuela was assessed. Single stool specimens were collected from 310 children 0-60 months of age with acute diarrheal disease who were admitted to three public hospitals and from 150 comparable control children without gastrointestinal symptoms who were seen as outpatients. Cryptosporidium parvum oocysts were identified in 35 (11.2%) of 310 children with diarrhea and the coccidium was the single detectable pathogen in only 12 (34.2%). Other potential pathogenic parasites were present in most of the patients shedding oocysts (23 of 35, 65%). In nondiarrheal control children, oocysts were identified in nine (6%) of 150. The data suggest that C. parvum is relatively highly endemic in children 0-60 months of age in Zulia State and that although C. parvum may be an important pathogen associated with diarrhea, it may be a cause of only a small proportion of diarrheal episodes.

Cryptosporidium infections in a suburban community in Maracaibo, Venezuela

A point prevalence survey for Cryptosporidium was conducted in 212 subjects two months to 70 years of age in a suburban area with a low socioeconomic status in Maracaibo City, Venezuela. Single stool specimens were collected and modified Ziehl-Neelsen carbol-fuchsin staining of 10% formalin-preserved stool was used to identify Cryptosporidium oocysts. Direct wet mounts, iron-hematoxylin-stained smears and formalin-ether concentrates were examined to determine the presence of other intestinal parasites. Cryptosporidium infections were identified in 21 subjects (9.9%), with a high percentage of asymptomatic carriers (15 of 21, 71.4%). Six children (28.5%) had gastrointestinal symptoms and four of them were infants. Cryptosporidium was the single detectable potential pathogenic parasite in only five (23.8%) of 21 patients. The infection rate with one or more parasites was high (82%) and multiple infections, including pathogenic helminths and protozoa, were observed in the majority of patients who passed oocysts. Our findings suggest that although Cryptosporidium is an important pathogen, the proportion of asymptomatic carriers may be high in areas of low socioeconomic status in developing countries.

Cryptosporidiosis among patients with acquired immunodeficiency syndrome in Zulia State, Venezuela

We studied the prevalence of Cryptosporidium in 29 patients with acquired immunodeficiency syndrome (AIDS) from Zulia State, Venezuela. They ranged in age from five months to 46 years. Two were children and 27 were adults, of which six were women. Of the 21 men, 66.6% reported homosexual behavior. Three stool samples from each patient were examined, and modified Ziehl-Neelsen carbolfuchsin staining of formalinether stool concentrates was used to identify Cryptosporidium oocysts. To detect the presence of other intestinal parasites, direct wet mounts and iron-hematoxylin-stained smears were examined. Cryptosporidium was found in 12 (41.3%) of the patients and was identified as a single parasitic infection in seven of the 12 patients (58.3%). Other pathogenic parasites encountered were Giardia lamblia (3 of 12, 25%), Entamoeba histolytica (1 of 12, 8.3%), Ascaris lumbricoides, Trichuris trichiura, and Strongyloides stercoralis (each 1 of 12, 8.3%). Blastocystis hominis, an organism with an uncertain taxonomic position and pathogenicity, was observed in three of 12 patients (25%). An inflammatory exudate was observed in 10 of 12 patients infected with Cryptosporidium. Most of the patients with this infection presented with chronic watery diarrhea and weight loss. Our results suggest that Cryptosporidium is very common in AIDS patients with diarrhea in Venezuela. However, the role of this parasite as an enteropathogen in these patients is uncertain.

Prevalence of Entamoeba histolytica and other intestinal parasites in a community from Maracaibo, Venezuela

The prevalences of Entamoeba histolytica and other intestinal parasites were assessed in a suburban community of Maracaibo, Venezuela, by examination of a stool specimen from each of 342 individuals, using iron-haematoxylin stained faecal smears and formalin-ether concentration. The overall parasitic infection rate was 80.4%, and 65.8% of the population had multiple infections. The overall amoebic infection rate, which was highest in female adults, averaged 39.7%. The E. histolytica infection rate was 8.7% and most of those infected were passing cysts. Entamoeba polecki was observed in two samples. Amongst the protozoa, Entamoeba coli was observed most frequently (24.8%) and Giardia lamblia was the predominant pathogen (13.0%). Trichuris trichiura (71.9%) and Ascaris lumbricoides (54%) were the most common parasites, particularly in school-children. The high rates of parasitic and multiple infections reflect the low socio-economic status of the community studied.

[Seroepidemiologic study of amebiasis in a community of the State of Zulia, Venezuela]

In the present evaluation, a community of low socioeconomical conditions from Zulia State, Venezuela, was analyzed for the prevalence of antibodies to E. histolytica. Two hundred and eighty three serum samples were collected and examined by the indirect hemagglutination test according to a microtiter modification of the KESSEL and LEWIS method, as used by MILGRAM et al. Antigen prepared from axenically-grown. E. histolytica strain HK9 in Diamond's medium was used. The seropositivity rate obtained was 46.6% and the frequency of positive cases was dependent on age. The antibody profiles obtained suggest a high endemicity for this parasitic infection in the area studied, with a much higher level of transmission than invasive amebiasis.

Successful treatment of human Entamoeba polecki infection with metronidazole

A 24-year-old woman with Entamoeba polecki infection was succesfully treated with metronidazole in a dosage of 750 mg orally thrice daily for 5 days. Examination of two direct smears and two formalin-ether concentrates from specimens collected at 2 days, 1 week, 1 month, and 2 months after the conclusion of therapy revealed no amebae. An indirect hemagglutination test for antibodies to E. histolytica gave a low positive titer of 1:128.