Workshop on research priorities for management and treatment of angiostrongyliasis(1).

In a concluding session of the workshop, the participants developed a list of 115 research and outreach needs, outlining the top 5-7 needs in each of 8 areas (Table). For complete information, including presenter details and abstracts, visit the workshop website at www.hawaii.edu/cowielab/Angio%20website%20home.htm.

Associations between two trematode parasites, an ectosymbiotic annelid, and Thiara (Tarebia) granifera (Gastropoda) in Jamaica.

This work describes associations of Thiara (Tarebia) granifera, its larval trematode community, and Chaetogaster limnaei limnaei at a freshwater reservoir in Jamaica. Larvae of 2 trematodes were present, i.e., a notocotylid (15.3%) and Philophthalmus sp. (1.3%), in 3,575 T. granifera examined. The prevalence of both infections increased with snail shell length (H  =  56, P < 0.01, H  =  23.1, P < 0.01, respectively). Only 3.0% (n  =  595) of infected snails possessed reproductive stages, compared with 90.3% (n  =  2,980) of uninfected snails (χ(2)  =  2,059.8, df  =  1, P < 0.001); both trematodes negatively impacted snail reproduction. Chaetogaster l. limnaei occurred within the mantle cavity of T. granifera with a prevalence of 2.3% (n  =  3,575); intensity ranged from 1 to 6 annelids. Notocotylid larvae occurred in 32.5% (n  =  83) of snails also harboring C. l. limnaei, compared with 14.9% (n  =  3,492) of snails lacking the annelid (χ(2)  =  18.127; P < 0.001). Chaetogaster l. limnaei appears not to influence the recruitment of egg-transmitted, notocotylid infections to snails. Ingestion of emergent cercariae by the annelid was observed; this may impact transmission of the parasite. The article presents the first report of a notocotylid and C. l. limnaei in T. granifera, and of Philophthalmus sp. in Jamaica.

Population distribution and zoonotic potential of gastrointestinal helminths of wild rats Rattus rattus and R. norvegicus from Jamaica.

The population distribution and zoonotic potential of gastrointestinal helminths in a naturally infected population of wild rats (Rattus rattus and Rattus norvegicus) in Jamaica are described. One hundred and thirty (29.7%) of 437 rats captured in the study were infected: 104 (35%) of 297 R. rattus compared with 26 (18.6%) of 140 R. norvegicus. Nine species of gastrointestinal helminths were recovered: Raillietina sp. (0.2%), Trichuris sp. (0.2%), Rictularia sp. (0.7%), Syphacia obvelata (1.1%), Strongyloides ratti (1.4%), Hymenolepis diminuta (3.8%), Protospirura muricola (4.3%), Moniliformis moniliformis (11.2%), and Nippostrongylus brasiliensis (14.2%). In a logistic model, the single risk factor identified for both M. moniliformis and P. muricola was R. rattus, compared with R. norvegicus (OR = 8.369 and 9.714, respectively). In comparison, the risk factor predicted for infection with N. brasiliensis was the northeastern section of Jamaica (OR = 11.000) compared with western Jamaica. Rictularia sp. represents a new geographic distribution record for the Caribbean region. Hymenolepis diminuta, M. moniliformis, Raillietina sp., and Rictularia sp. are potentially zoonotic, but only human infection with H. diminuta has been previously reported in the Caribbean.

Enzootic Angiostrongylus cantonensis in rats and snails after an outbreak of human eosinophilic meningitis, Jamaica.

After an outbreak in 2000 of eosinophilic meningitis in tourists to Jamaica, we looked for Angiostrongylus cantonensis in rats and snails on the island. Overall, 22% (24/109) of rats harbored adult worms, and 8% (4/48) of snails harbored A. cantonensis larvae. This report is the first of enzootic A. cantonensis infection in Jamaica, providing evidence that this parasite is likely to cause human cases of eosinophilic meningitis.

Report of ezootic Angiostronglyus cantonesis from Jamaica [ABSTRACT]

OBJECTIVE: To study the status of infection with Angiostrongylus cantonensis in wild rats and snails in Jamaica following an outbreak of eosinophilic meningitis amongst tourists. METHODS: One hundred and thirty-one Rattus rattus and 94 R norvegicus were collected, mainly from the eastern portion of Jamaica. The animals were dissected and the heart and pulmonary arteries explored to reveal A cantonensis. Similarly, several species of land snails were collected. A portion of the head/foot was excised, fragmented and placed in separate dishes of digestion fluid (0.01 percent pepsin in 0.7 percent v/v aqeous HCI). Dishes were examined for nematode larvae 4-5 hours and 24 hours post-digestion. A microscopical comparison of larvae with museum specimens confirmed identification. RESULTS: Overall, significantly more R rattus (42.7 percent) than R morvegicus (21.3 percent) were infected (x2=11.28;p<0.0001). Considering only those parishes where 15 or more rats were collected (Hanover, Manchester, St.James, St. Elizabeth, Kingston and St.Andrew, and Portland) the prevalence of rodent infections ranged from 6 to 59 percent. Of three snails and one slug species collected, only Thelidomus asper harboured A cantonensis larvae. This snail was collected from Manchester where the highest prevalence of rodent infections also occurred. CONCLUSIONS: The findings indicate that A cantonensis is present in rats and snails in Jamaica. In the context of reports (1996, 2000) of eosinophilic meningitis on the island, we recommend that public health officials, clinical parasitologists and travel medicine practitioners consider A cantonensis as a causative agent of eosinophilic meningitis in residents and travellers to Jamaica. (AU)

Seroepidemiology of Helicobacter pylori infection in a Jamaican community

We researched epidemiologic associations between environmental and demographic factors and prevalence of Heliobacter pylori infection in a suburban Jamaican community. Using a clustered sampling technique, 22 domestic yards enclosing 60 separate households were randomly selected from a local community. All household members (n=346) were invited to participate following informed consent; the overall compliance rate ws 58.9 percent. A detect IgG antibodies raised against H. pylori. Environmental and demographic information was obtained by questionnaire. The seroprevalence of H. pylori was 69.9 percent (n=202). Analysis of the independent variables revealed three major components: Component 1 described, collectively, good personal hygiene and sanitation, indoor water supply and absence of straying animals in the peridomestic area; Component 2 included older age, good personal hygiene and large yard size; Component 3 the presence of domestic animals (cats and dogs) and again, large yard size. These three complexes explained 42.2 percent of the variability in the data set. Logistic regression showed that Components 2 and 3 were independently associated with H. pylori seropositivity, indicating that a combination of demographic, environmental and zoonotic factors is involved in the spread of H. pylori infections at the tropical community level. (AU)

Short report: long-term serum antibody isotype responses to Strongyloides stercoralis filariform antigens in eight patients treated with ivermectin

The enzyme-linked immunosorbant assay was used to investigate long term changes in serum immunoglobulin G1 (IgG1), IgG4, IgE, and IgA against Strongyloides stercoralis phosphate-buffered saline-soluble filariform larval antigens in eight Jamaican patients treated with ivermectin. Patients were followed for periods of between 170 and 542 days. Based on repeated formalin-ether concentration and agar plate culture, all patients were found to be uninfected up to 18 months following chemotherapy. Generally, all antibody isotype levels decreased following treatment, although there was considerable heterogeneity among patients. In a single patient with hyperinfection, the decrease in IgG4 was marginal and may represent a treatment failure. Reduction in serum antibody isotype responses to S. stercoralis following treatment may be used to assess the effectiveness of ivermectin in treating endemic strongyloides (AU)

Treatment of patients infected with Strongyloides stercoralis using ivermectin: assessment of efficacy and safety - abstract

Infections with Strongyloides stercoralis are often refractory to thiabendazole therapy in certain patients. Ivermectin is being used increasingly for treatment of uncomplicated infections; however, possible immunopathological changes associated with drug-induced release of antigens as observed with use of the drug in filariasis has not been studied in strongyloidiasis. In this study we used the enzyme linked immunosorbant assay (ELISA) technique to examine the profiles of S. stercoralis-specific IgG4, IgE and IgA against saline soluble filariform extracts in 8 patients treated for the parasite. All patients were found to be negative for the parasite by stool examination following treatment. Isotype levels fell in concert following treatment although there was considerable heterogeneity among patients. Levels remained low following treatment response but were still measurable for up to eighteen months post-treatment. There appeared to be no rapid release of parasite antigens following treatment. One patient exhibited a transient increase in levels of IgA after which there was a decline in this and all other isotypes. The single patient with proven chronic infection and a history of gastrointestinal symptoms exhibited almost ablated IgG1, IgE and IgA responses prior to treatment but had a significant IgG4 response which remained high following treatment. The reduction in antibody levels post-treatment may be used as confirmation of parasitological cure. The study showed that there was no rapid release of S. stercoralis antigens as seen in filarial infections and that Ivermectin is safe and effective against the parasite (AU)

Parasitic infections associated with HIV/AIDS in the Caribbean

This review article seeks to highlight the significance for the Caribbean of major parasitic infections associated with AIDS, encourage awareness of these opportunistic parasites, and promote familiarity with appropriate diagnostic techniques and their clinical relevance. Specific agents considered include Pneumocystis carinii; Toxoplasma gondii; the enteric coccidians Crytosporidium spp., Isospora belli, and Cyclospora cayetanensis; the hemoflagellates Leishmania spp. and Trypanosoma cruzi; the fungi Histoplasma capsulatum and Cryptococcus neoformans; the nematode Strongyloides stercoralis; and the mite Sarcoptes scabiei. These disease agents can be divided into two groups, the immune-regulated "endogenous" parasites (the protozoans P. carinii and T. gondii, and possibly the roundworm S. stercoralis) and intracellular parasites (including the enteric coccidia, hemoflagellates, and fungi). Both in the Caribbean and elsewhere, the endogenous parasites (particularly P. carinii and T. gondii) are the most troublesome for AIDS patients, partly because they are likely to be transmitted and establish a benign immunoregulated presence early in the subjects's life. Indeed, health management programs for AIDS patients often routinely include P. carinii prophylaxis, since nearly all such patients who survive long enough are expected to experience an episode of acute P. carinii infection. In contrast, there is no known epidemiologic association between AIDS and strongyloidiasis in the Caribbean, and the prevalence there of potentially opportunisitc hemoflagellates such as Leishmania spp. and Trypanosoma cruzi is relatively low (AU)

Serum isotype responses in patients infected with Strongyloides stercoralis following treatment with ivermectin - abstract

Infections with Strongyloides stercoralis occur worldwide and can cause significant morbidity and mortality in man. They are often refractory to conventional chemotherapy especially in immunocompromised individuals. Recent studies have shown that Ivermectin is a safe and effective drug for use in uncomplicated infections. In this study, the profiles of parasite-specific IgG1, IgG4, IgE and IgA against a PBS soluble S. stercoralis filariform extract following treatment with ivermectin were investigated using the enzyme-linked immunosorbant assay (ELISA) technique. A series of 8 patients with parasitologically proven strongyloidiasis were treated with ivermectin and followed up for periods of 5 to 18 months. The predominant isotype found in the sera of patients from this series was IgG. High levels of IgG1 were recorded in young individuals while IgG4 was predominant in older persons. Levels of all isotypes declined following treatment and remained low up to eighteen months. Furthermore, no parasitological evidence of S. stercoralis infection was found after treatment, using agar plate and formalin-ether concentration methods. The reduction in antibody levels of post-treatment may be used as an indicator of adequate treatment and also demonstrate that patients are not exposed to drug-induced antigens following treatment. The study of S. stercoralis specific isotype profile will be useful in immuno-epidemiological studies in communities (AU)

Age-prevalence and household clustering of Strongyloides stercoralis infection in Jamaica

The epidemiology of Strongyloides stercoralis was studied in families of clinical (reference) cases and their neighbours at endemic foci in Jamaica. Thirteen foci were studied based on the place of residence of a reference case. For each household of a reference case, the 4 most proximal neighbourhood households (spatial controls) were included in the study. Out of 312 persons contacted 244 were followed up using questionaires, stool examimation and serology. Prevalence of infection based on based on stool examination was 3.5 percent and on ELISA 24.2 percent. Prevalence increased with age but was not related to gender. Reference cases were significantly older than the general study population. The prevalence of infection based on both serology and stool examination was significantly higher in referecne than in neighbouring households (the reference cases, themselves, were not included in the analysis). Furthermore, prevalence of infection was highest among persons who shared a bedroom with a reference case and decreased significantly with increasing spatial separation. This is indicative of close contact transmission which has not been previously shown for a geohelminth, but which is common among microparasites.(AU)

Endoreplication in the ovary, testis, and intestine of strongyloides sterocalis

During development of the free-living adults of the human parasitic nematode Strongyloides stercoralis, cells in certain tissues grow by endoreplication in which rounds of DNA replication occur without cell or nuclear division. The DNA content of individual nuclei was measured by microdensitometry of Feulgenstained preparations. In females, some ovarian cells have up to 800 times the haploid DNA content (800C). In males, some cells of the testis have up to 100C. Intestinal cells in both sexes have up to 16C, whereas most other somatic cells have 2C (AU)

Strongyloides stercoralis: characterization of immunodiagnostic larval antigens

Forty-one-, 31-, and 28-kDa proteins of strongyloides stercoralis filariform larvae have previously been demonstrated to be sensitively and specifically recognized by serum IgG in individuals with strongyloidiasis. Characteristics of these proteins, their immunodominant epitopes, and reactive antibodies are described here. The proteins are soluble is aqueous as well as detergent extracts. The immunodominant epitopes are present in S. stercoralis but not in S. cebus or S. ratti. Epitopes on the three proteins are not shared, as determined by cross-absorption of serum with each of the size components on nitrocellulose. In most sera from strongyloidiasis patients there was reactivity to each of the proteins by IgG1 and IgG4, but reactivity by IgG2 or IgG3 was detectable only in a minority. A rabbit antiserum raised to a 41-kDa size fraction of S. stercoralis larvae reacted against a doublet of 41-kDa which was distinct from the immunodiagnostic 41-kDa protein.(AU)

Prospective evaluation of enzyme-linked immunosorbent assay and immunoblot methods for the diagnosis of endemic Strongyloides stercoralis infection

Recently described enzyme-linked immunosorbent assay (ELISA) and immunoblot methods for the detection of serum IgG against Strongyloides stercoralis larval antigens were prospectively evaluated for the diagnosis of endemic strongyloidiasis. A modification of the ELISA involved preincubation of sera with Onchocerca gutturosa phosphate-buffered saline-soluble extract to remove cross-reactivity with other helminths. The sensitivity of the ELISA increased from 80 percent and 85 percent following preincubation. Similarly, there was an increase in specifity from 94 percent to 97 percent. The IgG recognition of 41-, 31-, and 28-kD filariform larval components showed sensitivities of 100 percent, 85 percent and 65 percent, respectively. Both the ELISA following incubation of sera with O. gutturosa extract and serum IgG reactivity to a 41-kD larval component using immunoblotting are sensitive and specific techniques for diagnosing endemic strongyloidiasis.(AU)

Age-prevalence profile and household clustering of cases of strongyloides infection at endemic foci at Jamaica - abstract

Strongyloides sterocalis infections were examined in families of clinical cases and also in those of their most proximal neighbours. Thirteen clinical cases in Kingston, Jamaica led to the identification of thirteen endemic foci. In addition to the clinical cases, 299 persons were contacted using questionnaires, stool examination and serology. Two hundred and thirty-one persons were fully compliant. The stool prevalence of S.sterocalis was 3.5 percent, while that based on ELISA was 24.2 percent (not including the 13 clinical cases). Both estimates of infection prevalence were significantly higher in the households of the clinical cases compared with the neighbours. The clinical cases were significantly older than the general study population. Furthermore, prevalence was highest among persons who shared a bedroom with a clinical case and decreased with spatial separation. These data strongly suggest that human strongyloides is a close-contact infection. This is likely to be facilitated by the direct phase of the parasite's life cycle and has significant implications for control of infections in endemic areas (AU)_

Immunoepidemiologic studies of Strongyloides stercoralis and human T lymphoropic virus type I infection in Jamaica

Epidemilogic investigations of Strongyloides stercoralis and human T lymphotropic virus type I (HTLV-I) infections were conducted. Of 312 persons contacted, 209 (67 percent) provided blood and stool samples. Prevalences of S. stercoralis and HTLV-I antibodies were 26.8 percent and 8.1 percent (n = 198), respectively, and S. stercoralis larvae were detected in 4 percent. HTLV-I antibodies were significantly more common in persons positive for S. stercoralis larvae (10 [58.8 percent] of 17) compared with seropositive larvae-negative (4 [8.9 percent] of 45) or seronegative persons (9 [6.2 percent] of145) (P< .002). IgE levels increased with age in S. stercoralis-seropositive persons who were HTLV-I negative (P, .))2). However, there was an age-related depression of serum IgE in HTLV-I-positive persons (P < .003) that was sufficient to annul the IgE level-raising effect of S stercoralis seropositivity. The data provide evidence that HTLV-I infection is associated with increased frequency of larvae in the stool of S. stercoralis-infected persons and suggest that the mechanism may involve suppression of the IgE response (AU)