Platynosomum fastosum-induced chronic intrahepatic cholangitis and Spirometra spp. infections in feral cats from Grand Cayman.

The occurrence of platynosomiasis and intestinal sparganosis is described in feral cats from Grand Cayman, Cayman Islands. Spirometra spp. was observed within the intestine of 18.18% (10/55) of cats; 1.18% (1/55) of cats demonstrated gross and histological manifestation of parasitism by Platynosomum fastosum, but 14.5% (8/55) of cats had the characteristic pathological manifestations of P. fastosum-induced intrahepatic cholangitis without the concomitant presence of the intraductal trematode. Combined parasitism (Spirometra spp. and P. fastosum) was observed in 9.09% (5/55) of feral cats. Significant pathological findings were only associated with the hepatic fluke, P. fastosum, and were grossly characterized by moderate hepatomegaly with enlarged and dilated bile ducts. Examples of cestodes with morphological features characteristic of Spirometra spp. were observed within the small intestine without any associated pathological lesion. The histopathological evaluation of liver fragments revealed chronic intrahepatic cholangitis with and without the associated intraductal trematode, and was characterized by marked periductal fibrosis, adenomatous proliferation of bile duct epithelium, dilation of intrahepatic bile ducts and portal accumulations of inflammatory cells. The occurrence of the cestode in feral cats coupled with factors that are unique to Grand Cayman makes this island the ideal location for sporadic cases of human sparganosis.

Specific immunoglobulin measurements related to exposure and resistance to Schistosoma mansoni infection in Sudanese canal cleaners.

The present work comprises a longitudinal study of Schistosoma mansoni infection in occupationally hyper-exposed canal cleaners in the Sudan and the influence of chemotherapy on humoral immune parameters. The study groups included chronically infected canal cleaners (n = 19), newly recruited canal cleaners (n = 17), normally exposed adults (n = 31), school children (n = 46) and Sudanese negative controls (n = 48). Previous studies of the same canal cleaners have demonstrated that chronically infected canal cleaners were more resistant to reinfection than newly recruited canal cleaners. ELISA was used to detect specific IgE and IgG subclasses in response to whole worm antigen (WWH) and soluble egg antigen (SEA) before and 3 months after praziquantel treatment in the groups of canal cleaners and before and 1 year after treatment in normally exposed adults. When intensity of infection was correlated with IgE antibody response, the resistant group of canal cleaners (those who stopped passing ova after treatment) showed a significant positive correlation between intensity of infection and specific IgE to WWH (Spearman's correlation coefficient = 0.49, P < 0.05) compared with a highly significant negative correlation in the susceptible group (acquired new infection after treatment, Spearman's correlation coefficient = -0.94, P < 0.01). Normally exposed adults and school children had significantly less specific IgE to WWH than canal cleaners, while chronically infected canal cleaners had significantly higher levels of specific IgG1 to WWH than newly recruited canal cleaners and school children, and significantly higher levels of specific IgG4 to WWH than school children. There was a significant increase in specific IgG1 and IgG4 to WWH, 3 months after treatment, in newly recruited canal cleaners and a significant decrease, 1 year after treatment, in normally exposed adults. None of the groups studied after treatment showed a significant change in their specific IgE to WWH. Normally exposed adults had significantly lower levels of specific IgE to SEA than newly recruited canal cleaners, and significantly lower levels of specific IgG1 to SEA than other infected groups. Both newly recruited canal cleaners and school children had significantly higher levels of specific IgG2 to SEA than persons in other groups. Only small differences between groups were observed with regard to specific IgG3 and IgM to SEA. Specific IgG4 to WWH and SEA showed different patterns after treatment between the resistant and susceptible groups of canal cleaners. The resistant group maintained the same level of IgG4 to WWH after treatment compared with a significant increase in the susceptible group. On the other hand, levels of specific IgG4 to SEA showed a highly significant decrease after treatment in the resistant group. In contrast, the same antibody subclass increased after treatment in the susceptible group. Generally, results show an association between IgE and IgG1 responses to WWH and resistance to reinfection. In contrast, an association was observed between IgG2 and IgM responses to SEA and susceptibility to reinfection.

Use of a new glass microfibre histamine release method to study the modulation of the host response in human schistosomiasis mansoni. Individuals with different degrees of exposure to the disease show differing antibody biological function.

A new glass microfibre histamine release method was used to study the modulation of the host response in human schistosomiasis mansoni to improve our understanding of the role of basophils in the development of immunity in schistosomiasis mansoni. The histamine release from umbilical cord blood basophils sensitized with sera from Sudanese individuals infected with Schistosoma mansoni was measured. Schistosomiasis sera (n = 113) were able to passively sensitize basophils and induce a positive histamine release in response to whole worm homogenate (WWH) (chi 2 = 40.5, P < 0.0001) and soluble egg antigen (SEA) (chi 2 = 16.3, P < 0.0001). However, worm antigen induced significantly higher histamine release in adults than egg antigen (Z = 4.83, P < 0.0001). Basophil cell sensitivity to WWH was inversely related to the intensity of infection. A correlation was observed between basophil cell sensitivity and IgE antibodies in response to WWH. Chronically infected canal cleaners (n = 16) showed a significant increase in basophil cell sensitivity 3 months after praziquantel treatment (Z = 1.73, P < 0.05). Normally exposed adults (n = 29) showed a significant decrease in basophil cell sensitivity 1 year after treatment. When serum fractions were used, chronically infected canal cleaners showed a significant increase in histamine release after IgG removal (P < 0.05) Comparison between the different study groups with regard to resistance and susceptibility to reinfection, their basophil sensitizing ability and antibody response showed a difference in the biological function of the IgE to WWH in the different groups. Direct histamine release results from S. mansoni infected individuals from outside the endemic area (Danish) showed the possibility of using the glass microfibre histamine release method in the diagnosis of schistosomiasis.

Clinical, parasitological and immunological features of canal cleaners hyper-exposed to Schistosoma mansoni in the Sudan.

The present work was a longitudinal study on Schistosoma mansoni infection in occupationally hyperexposed canal cleaners in the Sudan and the influence of therapy on the parasitological and humoral immune parameters. Chronically infected canal cleaners (n = 28) were more resistant to reinfection (Fisher's exact test, P < 0.05) than newly recruited canal cleaners (n=17). Chronically infected canal cleaners had a significantly higher degree of Symmers' fibrosis (chi2 = 19.1, P < 0.0001), significantly larger portal vein diameter (P < 0.05) and enlarged spleen (chi2 = 4.2, P < 0.05) than recently infected, newly recruited canal cleaners. ELISA was used to detect IgG, IgA and IgM in response to whole worm homogenate (WWH) and cercarial homogenate (CH). Chronically infected canal cleaners had significantly higher IgG to WWH antigen than newly recruited canal cleaners and normally exposed individuals (P < 0.05), while both chronically infected and newly recruited canal cleaners had higher IgG levels to CH antigen than normally exposed individuals (P < 0.05). The newly recruited canal cleaners had a significantly higher IgM level to CH antigen than chronically infected canal cleaners (P < 0.05). The IgG level to WWH antigen increased significantly after treatment in newly recruited canal cleaners and normally exposed individuals (P < 0.05). The IgA level to CH antigen increased significantly after treatment in the chronically infected group (P < 0.05). Comparison of the serological parameters between the different study groups with regards to infection and treatment is discussed.

Anti-filarial effects of nine quinoline-containing drugs on adult filariae in vitro.

The potencies and efficacies of 9 quinoline-containing anti-malarials including chloroquine, (bis)desethylchloroquine, SN6911, SN12108, amodiaquine, CN-2999-2K, primaquine, quinacrine, and quinine were examined in vitro against adult female Brugia pahangi. Parasite motility and lactate excretion were measured as indicators of drug effects. All of the agents tested showed time-dependent increases in potency over a 24-72-hr incubation period. SN12108 was the most potent at 72 hr, reducing motility by greater than or equal to 50% (IC50) at 1.0 x 10(-7) M. Chloroquine (IC50 2.3 x 10(-6) M), desethylchloroquine (IC50 7.0 x 10(-6) M), quinacrine (IC50 1.9 x 10(-6) M), and quinine (IC50 1.5 x 10(-5) M) were the least potent. All of the drugs caused time-dependent decreases in lactate excretion, except quinine; decreases were found to be dose dependent. A high correlation (r greater than 0.85) was seen between time-dependent effects on motility and lactate excretion. The effects of chloroquine (10 microM) on motility were also examined in female Acanthocheilonema viteae, Dirofilaria immitis, Onchocerca volvulus, and male Onchocerca gutturosa. Dirofilaria immitis was less sensitive to chloroquine than B. pahangi; A. viteae was equally sensitive. Species of Onchocerca were the most sensitive parasites studied. Adult O. gutturosa and O. volvulus were affected by 10 microM chloroquine within 4-6 hr; motility was reduced by 80% within 24 hr. Although the mechanism of anti-filarial activity of the quinoline-containing drugs is not known, their in vitro activity against a variety of adult filariae at clinically relevant concentrations, as well as differential sensitivity seen between the different filariae examined, warrants further study of these compounds.

Comparative effects of anthelmintics on motility in vitro of Onchocerca gutturosa, Brugia pahangi and Acanthocheilonema viteae.

The effects of standard anthelmintics on the motor activity in vitro of adult Onchocerca gutturosa, Brugia pahangi and Acanthocheilonema viteae were determined using a micromotility meter. Fresh adult males dissected from bovine tissues were the best source for observations on O. gutturosa. Parasites liber-ated by collagenase digestion showed poor viability and motility. Only segments of O. gutturosa females were obtainable by dissection and these were not able to sustain motility in vitro. Adult males and females of O. volvulus were active after collagenase digestion of human nodular tissue, but behaved so irregularly that satisfactory monitoring of their movements with the meter was not possible on a regular enough basis to permit quantitation of drug-induced changes. Inhibitory effects on motility of O. gutturosa, B. pahangi and A. viteae were produced by anthelmintics which showed macrofilaricidal effects in vivo in a laboratory rodent model, with the exception of the benzimidazoles. O. gutturosa was, however, much more sensitive than B. pahangi or A. viteae to the temporary paralyzing effects of levamisole and pyrantel. The utility of in vitro screening against O. gutturosa and B. pahangi was evaluated by determining the discriminatory capacity of the tests in detecting novel compounds with reproducible in vivo activity in the jird-B. pahangi/A. viteae model. The results suggested that this would be a valuable selective screening procedure. Although false positives were detected at the rate of 15-17% of the novel anthelmintic chemical series tested, no false negatives were allowed through the screen provided both O. gutturosa and B. pahangi were included.2=