Case report: the first parasitologically confirmed autochthonous case of acute Chagas disease in Suriname.

We present a case report from 2001 of the first parasitologically confirmed case of acute Chagas disease in Suriname. The patient had never left Suriname, and was probably infected by an adventitious species of Panstrongylus in his house in the capital city, Paramaribo. The patient was treated with nifurtimox, and appears to have recovered.

The occurrence of polycystic echinococcosis in Suriname.

The occurrence of polycystic echinococcosis (PE) caused by Echinococcus vogeli in Suriname is reviewed. Six of the eight known cases, including the first (which was incorrectly diagnosed as cystic hydatid disease caused by E. granulosus) in 1982, are described. The distribution in Suriname of the natural hosts of E. vogeli--the bush dog (Speothus venaticus) and the paca (Agouti paca)--is discussed. Characteristics of the four species recognized in the genus Echinococcus are compared, and all known cases of PE in 11 countries in the Neotropics are summarized. Finally, it is stressed, that, in Suriname, PE should be considered during the differential diagnosis of all subjects from rural areas who present with abdominal pain and palpable, intraperitoneal masses.

Lymphatic filariasis in the Caribbean region: the opportunity for its elimination and certification.

In order to support the case for a certification of elimination of lymphatic filariasis (LF) in some Caribbean countries, we compared the prevalence of circulating Wuchereria bancrofti antigen in communities in Guyana, Suriname, and Trinidad. For the study, we assayed school children in six communities in Guyana, five communities in Suriname, and three communities in Trinidad for the prevalence of circulating W. bancrofti antigen, using a new immunochromatographic test for LF. We also assayed adults in these three countries, with a special focus on Blanchisseuse, Trinidad, where mass treatment for LF elimination had been carried out in 1981. The prevalences of W. bancrofti circulating antigen found in the school children populations ranged from 1.7% to 33.2% in Guyana and were 0.22% overall in Suriname and 0.0% in Trinidad. Among adults in two Guyana communities the prevalences were 16.7% and 32.1%. The results were all negative from 211 adults in communities in the north, center, and south of Trinidad, as well as from 29 adults in Suriname. The data suggest that contrary to reports of LF endemicity from the World Health Organization, LF may no longer be present in Trinidad and may be of very low prevalence in Suriname. Trinidad and Tobago and other Caribbean nations proven negative could seek to be awarded a certificate of LF elimination. In Suriname the small localized pocket of infected persons who may serve as a reservoir of LF infection could be tested and appropriately treated to achieve LF elimination. Such LF-positive countries as Guyana should access new international resources being made available for LF elimination efforts. An adequate certification program would help identify which countries should seek the new LF elimination resources.

Validation of a chart to estimate true Schistosoma mansoni prevalences from simple egg counts.

Schistosoma mansoni egg counts by faecal examination vary considerably and are not very sensitive, so prevalences are underestimated. The distribution of egg counts can adequately be described by a stochastic model which distinguishes variation in counts between persons and variation in repeated counts within a person. Based on this model a pocket chart has been developed which predicts the proportion of individuals harbouring at least 1 S. mansoni worm pair-the 'true prevalence'-from a simple single survey prevalence and geometric mean egg count (using common duplicate 25 mg Kato-Katz smears). The current paper describes the validation of this chart by comparing predicted true prevalences with prevalences observed after 5-7 repeated Kato-Katz faecal examinations (Burundi), by examination of a large quantity of stool using the Visser filter (Brazil) or a selective sedimentation-filtration method (Surinam). Because 5-7 repeated examinations do not suffice to measure all infections, predictions have been made of the cumulative proportion positives over 5-7 surveys-the 'approximate true prevalence'-as well. After dividing the data into age groups, 12 different subsets were considered for validation. In all 12 cases, predicted true prevalences (or approximate true prevalences for the Burundi data) agree well with those observed. The overall agreement depends only slightly on the assumed relationship between worm numbers and mean egg counts, with a good fit for a productivity between 0.8 and 4.4 eggs per gramme faeces (EPG) per worm pair (WP). This interval includes the most plausible value from the literature, i.e. 1.0 EPG/WP, which has been applied in the initial pocket chart. These findings support the validity of the chart to predict true prevalences for a wide range of productivity assumptions, and reinforces the applicability of its underlying stochastic model to describe egg count variation. However, as predictions appear to vary importantly when using only part of the data, it is also concluded that the pocket chart never compensates for limited validity of initial single survey prevalences and geometric means in consequence of small sample sizes.

Immunodiagnosis of schistosomiasis mansoni in a low endemic area in Surinam by determination of the circulating antigens CAA and CCA.

We evaluated the applicability of circulating antigen detection in serum and urine for the diagnosis of Schistosoma infections in a low endemic area. In total 389 individuals from Saramacca (Surinam) participated in the survey. Stool samples were examined using the Kato method, while circulating anodic antigen (CAA) and circulating cathodic antigen (CCA) were determined by highly specific monoclonal antibody-based ELISA's. Also schistosome specific IgM antibodies were measured by the indirect immunofluorescence assay, but the diagnostic performance of this test was found to be poor in this population. S. mansoni eggs were found in 29% of the examined cases, while CAA and CCA could be demonstrated in 23% and 17% of the serum samples and in 3% and 28% of the urine samples, respectively. Forty three percent of the study population was positive in at least one of these diagnostic assays, indicating that each individual test misses a substantial part of the subjects with an active infection. In most positive cases, intensities of infection were very low. As 204 individuals participated in all screening assays, diagnostic performance of each test was evaluated in this sub-population. The highest sensitivities were achieved with the urine-CCA assay and the parasitological examination, detecting 59 and 58 out of the 107 cases with an active infection, respectively. The serum-CAA assay detected 47 positive cases. Our results demonstrate that determination of circulating antigens, especially CCA in urine and CAA in serum, provides information additional to the parasitological examination, for the assessment of prevalence and intensity of Schistosoma infection in low endemic areas.

A sedimentation-selective filtration method for the diagnosis of light infections with Schistosoma mansoni.

An epidemiological survey for infection with Schistosoma mansoni was carried out in the community of Catharina Sophia in northern Surinam. The merits of a more sensitive diagnostic system, the Sedimentation-Selective-Sieving (SSF) method, were evaluated; the results were compared with those obtained with the standard Kato-Katz thick smear technique. Examination of a duplicate Kato smear (2 x 25 mg) resulted in a prevalence of 22% while the real prevalence was shown to be more than 42%. The SSF procedure was shown to have a comparatively high sensitivity although the egg counts per gram (calculated on the basis of examining samples of 2-3 g) were considerably lower than those derived from Kato smears. The implications for epidemiological surveillance of communities with excretion of low numbers of S. mansoni eggs are discussed and the observations are compared with those one might expect on the basis of mathematical modelling (De Vlas et al., 1992).

Detection of hookworm and hookworm-like larvae in human fecocultures in Suriname.

Estimation of the prevalence of hookworm infection is usually based on finding eggs of the parasite in the stool. Eggs of the different hookworm species are difficult to distinguish and can be confused with those of hookworm-like species. Proper identification can be made after hatching the eggs and cultivating larvae to the infective stage. We have used the Harada-Mori method to study the stools of Bushnegroes in Suriname and have identified the emerged larvae. Of the 804 individuals examined, 53.6% had positive fecal cultures. The identification of emerged larvae revealed that 75% of the positive cultures contained Necator americanus and Strongyloides stercoralis was detected in 19.7%. Oesophagostomum and Ternidens species were also found. Ancylostoma duodenale larvae were not found. Six percent of fecal cultures in which larvae emerged contained only hookworm-like larvae hatching from eggs that resembled hookworm eggs. The diagnosis of hookworm infection, based solely on the microscopic detection of eggs in the stool, must be considered with special caution.

The sixth case of lagochilascariasis minor in Surinam.

The sixth case of lagochilascariasis minor in Surinam is reported in a 13-year-old boy. He had abscesses on the right and left side of the neck, with fistulae out of which eggs, larvae and adult worms were expelled. Treatment with thiabendazole and levamisole were ineffective. Finally he was cured after prolonged treatment with albendazole. This is probably the 63rd case of lagochilascariasis minor in the world, but there is a possibility that infection with this rare nematode is underreported.

Efficacy of mosquito nets treated with permethrin in Suriname.

In the rain-forest of Suriname, where malaria is endemic, 95% of the Maroons (who call themselves bush-negroes) and all Amerindians use mosquito nets made of cotton cloth or, less frequently, nylon or cotton gauze over their hammocks or beds. Bush-negroes usually wash their nets weekly; Amerindians wash nets at 1-4 month intervals. Females of the principal local malaria vector, Anopheles darlingi Root, were seen blood-feeding through cotton cloth netting (at 22.30-23.30 hours) on a person sleeping in a hammock; others fed successfully after the net was opened in the morning. Cotton cloth impregnated with permethrin at a rate of 0.5 g/m2 killed all An. darlingi females exposed for 2 min, but after the material had been washed twice in soapy water the bioassay mortality fell to only 21.4%. Exit traps on a hut with a single sleeper protected by a permethrin-impregnated net yielded 185 An. darlingi females (12% blood-fed) in 74 nights, compared with 276 females (19% blood-fed) from another hut with a sleeper using an untreated net on the same nights (P less than 0.001). No An. darlingi females remained resting alive indoors in these huts during the daytime, and very few were found dead on the floor in the mornings (one treated, seven untreated). The 24 h mortality rate for those collected in exit traps was 58.4% for the test hut and 27.1% for the control hut (P less than 0.001). Bioassays of permethrin-treated cotton cloth using laboratory-reared sugar-fed Culex quinquefasciatus Say females showed that sprayed nets were less effective than nets impregnated by soaking (at equivalent dosages of 0.16-1.34 g/m2 measured by chemical assay) and confirmed that washing causes severe decline in insecticidal activity. The feasibility of local mass treatment of mosquito nets is discussed.

Behavioral responses of Anopheles darlingi in Suriname to DDT residues on house walls.

A study was conducted in Suriname on the effects of DDT residual house spray on the main vector of malaria, Anopheles darlingi. Results obtained with an experimental hut sprayed with DDT wettable powder (2 g/m2 AI) were compared with results obtained with an unsprayed control hut. In the sprayed hut, entry rates were reduced by 32% and feeding success by 43.6%. The 24-h mortality of mosquitoes which entered the sprayed hut was 95% (range 85-100%) over the 10-month study period. After furnishing the sprayed hut according to local custom, no reduction in mortality was observed despite an abundance of unsprayed resting surfaces. Bioassays showed that the DDT deposits remained effective for at least 14 months. With excito-repellency test boxes an irritant effect caused by DDT on recently fed An. darlingi females was shown. With a choice-box experiment no preference for unsprayed over sprayed resting places could be demonstrated.

Fansidar resistant Plasmodium falciparum infection in Surinam.

The first cases of Fansidar resistant Plasmodium falciparum infection in Surinam are reported after chloroquine-resistance was reported in 1972. The resistant cases were suspected by physicians and confirmed after performing the 35-day extended standard WHO 7-day in vivo-test. The distribution of drug resistant P. falciparum in Surinam is presented. The problem that drug resistance causes in the Malaria Eradication Program in Surinam is discussed.

Clonorchiasis in Surinam.

A 46-year-old Chinese male was admitted to the Deaconesses' Hospital in Paramaribo with severe bleeding from esophagus varices. After being first on a wrong track the diagnosis clonorchiasis was made. The case history of the patient is described. This was the second case of clonorchiasis in Surinam. It is emphasized that imported diseases must be considered, whenever immigrants show up with symptoms.

A seroepidemiological study of amebiasis in Surinam by the enzyme-linked immunosorbent assay (ELISA).

Sera from nine populations in Surinam, South America, were screened for antibodies against Entamoeba histolytica by the enzyme-linked immunosorbent assay (ELISA) technique and a precipitin test (gel diffusion or counterimmunoelectrophoresis). In two small surveys in 1974 and 1978, a high rate of clinically significant ELISA titers was found in a rather isolated group of Amerindians living near the Brazilian border, predominately in the youngest age groups. Amerindians living near the coast showed a low level of seropositivity. Low levels were also found in Bush Negro villages in the interior of Surinam and in Hindustani school children from the savannah area. A high frequency of ELISA titers greater than or equal to 320, indicating a high rate of invasive amebiasis, was detected in persons in a mental institution in Paramaribo. It is concluded that the ELISA, which is much more sensitive than the precipitin tests, is a useful screening test for assessing the prevalence of invasive amebiasis on an epidemiological scale.

Applicability of different antigen preparations in the enzyme-linked immunosorbent assay for schistosomiasis mansoni.

The applicability of seven different antigen preparations for the detection of antibodies against Schistosoma mansoni was tested in the enzyme-linked immunosorbent assay. For this purpose, sera from children and adults from Surinam infected with S. mansoni were screened for the presence of specific antibodies against the various antigens. With all antigens, generally better results were obtained with the sera from children than with those from adults. The best results were obtained when the trichloroacetic acid-soluble fraction of adult worm antigen (containing the proteoglycan circulating anodic antigen) was used.