Joyce Siwila

Seasonal prevalence and incidence of Cryptosporidium spp. and Giardia duodenalis and associated diarrhoea in children attending pre-school in Kafue, Zambia

Prevalence, incidence and seasonal variation of Cryptosporidium and Giardia duodenalis were studied over a 12-month period in 100 children from four pre-schools in Kafue, Zambia. Questionnaire data and a single stool sample were collected monthly from each child. Samples were processed using a commercial kit (Meridian Diagnostics Inc., USA) and oo(cysts) visualised by immunofluorescence microscopy. Cryptosporidium was detected in 30.7% (241/786; 95% CI = 27.5-33.9) while G. duodenalis was detected in 29.0% (228/786; 95% CI = 25.8-32.2). A total of 86% experienced one or more episodes of cryptosporidiosis while 75% had giardiasis. Cumulative incidence per 100 children was 75.4 for Cryptosporidium and 49.0 for G. duodenalis. Both infections were significantly more common in the wet compared to the dry season (34.8%, 162/466 vs. 24.7%, 79/320, P = 0.003 and 35.2%, 164/466 vs. 20.0%, 64/320, P < 0.001, respectively). Thus, risk ratios (RR) were 1.41 (95% CI = 1.13-1.77) and 1.76 (95% CI = 1.38-2.27) for Cryptosporidium and Giardia, respectively. Diarrhoea was significantly associated with cryptosporidiosis (RR = 1.23, 95% CI = 1.03-1.47; P = 0.029) but not with giardiasis (RR = 1.12, 95% CI = 0.91-1.53; P = 0.26). We conclude that gastro-intestinal protozoal infections are highly prevalent among children attending pre-school in peri-urban Zambia highlighting the need for further studies of risk factors.

Intestinal helminths and protozoa in children in pre-schools in Kafue district, Zambia.

Intestinal parasitic infections are among the most widespread of human infections in developing countries, and children are the most vulnerable. The aim of this study was to determine the prevalence of the protozoa Cryptosporidium and Giardia, as well as prevalence and intensity of intestinal helminths in children attending pre-school or day-care centres in Kafue District, Zambia. Single stool samples were collected from 403 children from 10 pre-schools and were subjected to duplicate Kato-Katz thick smears to identify and quantify helminths. A commercial immunofluorescence kit was used to identify Cryptosporidium- and Giardia-positive samples. The overall prevalence of helminth infection was 17.9%. Ascarislumbricoides was found in 12.0%, hookworm in 8.3%, Taenia spp. in 0.9%, Hymenolepisnana in 0.6% and Schistosomamansoni in 0.3%. The overall prevalence of Cryptosporidium and Giardia was 28.0 and 29.0%, respectively, with more girls infected with Giardia (33.8%) than boys (22.7%) (P=0.02). Significant differences in infections with A. lumbricoides and Cryptosporidium were observed between the various pre-schools (P < 0.001). These findings indicate that intestinal parasites are prevalent in children enrolled in pre-schools in Zambia. Future studies should explore local factors associated with transmission of these infections, and consequently provide the necessary health education to parents and teachers.

Prevalence of Cryptosporidium spp. and Giardia duodenalis in pigs in Lusaka, Zambia

This study was aimed at determining the prevalence of Cryptosporidium spp. and Giardia duodenalis in pigs which were being raised in intensive management systems. Faecal samples were collected from pigs of all age groups from three different piggery units. Samples were collected directly from the rectum for piglets and weaners and from the floor within 2 min - 5 min of excretion for sows and boars. At the time of collection, faecal consistency was noted as being normal, pasty or diarrhoeic. Samples were analysed further using the Merifluor® Cryptosporidium/Giardia immunofluorescence assay. All piggeries had at least one pig infected with either parasite. From a total 217 samples collected, 96 (44.2%; confidence interval [CI] = 37.6% - 50.9%) were positive for Cryptosporidium spp., whilst 26 (12%; CI = 7.6% - 16.3%) had G. duodenalis parasites. Of all the pigs, 6.9% (15/217) harboured both parasites. With regard to Cryptosporidium spp. infection, statistically significant differences were observed amongst the three units (p = 0.001), whereas no significant differences were observed for G. duodenalis infection (p = 0.13). Prevalence was higher in weaners as compared to other pig classes for both parasites, with significant differences being observed for G. duodenalis infection (p = 0.013). There was, however, no difference in infection between male and female pigs for both parasites. Furthermore, most infections were asymptomatic. From the study results it was clear that Cryptosporidium spp. and G. duodenalis infections were prevalent amongst pigs in the piggeries evaluated and, as such, may act as a source of infection for persons who come into contact with them.

Filarial infections in domestic dogs in Lusaka, Zambia.

Filariae are common parasites of dogs in many parts of the world, but little is known about the status of these infections in sub-Saharan Africa. A study was carried out to determine the occurrence and species of filariae among 272 dogs in Lusaka, Zambia. Giemsa stained blood smear and Knotts concentration methods revealed microfilariae in 16 (5.9%) of the dogs. PCR confirmed that most of these dogs had Acanthocheilonema reconditum infection. Ten (4.0%) of the examined dogs were positive for Dirofilaria immitis circulating antigen (by DiroCHEK(®) test), but D. immitis microfilariae were not identified in any of the dogs and the status of this infection remains unclear. Further studies are needed to explore the occurrence of filariae in Zambian dogs and the zoonotic potential for humans.

Prevalence of Giardia in dairy cattle in Lusaka and Chilanga districts, Zambia.

Giardia is an intestinal protozoan parasite of mammals including humans. A cross-sectional study was conducted to estimate prevalence of Giardia infections in smallholder and commercial dairy herds in Chilanga and Lusaka districts of Zambia. A total of 377 calves aged from 1 to 365 days were sampled on 34 farms. All faecal samples were analyzed for Giardia antigen using a commercially available ELISA kit. Overall prevalence of Giardia was 34.5% (95% CI=29.7-39.3). Among smallholder farms, animal level prevalence ranged from 0 to 100% (mean=44.6±36.9 standard deviations) and 12.5 to 60.9% (mean=33.5±16.7 standard deviations) within commercial herds. Prevalence was highest in calves less than three months old (p=0.010), and there was no significant difference in the prevalence between smallholder and commercial farms (p=0.300). Giardia prevalence was not associated with occurrence of diarrhoea in the calves (p=0.205). The study demonstrates that Giardia infections are common in dairy herds in the study areas, especially in calves less than three months of age.

Seroprevalence of Canine Parvovirus in Dogs in Lusaka District, Zambia

Canine parvovirus (CPV) enteritis is a highly contagious enteric disease of young dogs. Limited studies have been done in Zambia to investigate the prevalence of CPV in dogs. Blood was collected from dogs from three veterinary clinics (clinic samples, n = 174) and one township of Lusaka (field samples, n = 56). Each dogs age, sex, breed, and vaccination status were recorded. A haemagglutination assay using pig erythrocytes and modified live parvovirus vaccine as the antigen was used. Antibodies to CPV were detected in 100% of dogs (unvaccinated or vaccinated). The titres ranged from 160 to 10240 with a median of 1280. Vaccinated dogs had significantly higher antibody titres compared to unvaccinated (p < 0.001). There was a significant difference in titres of clinic samples compared to field samples (p < 0.0001) but not within breed (p = 0.098) or sex (p = 0.572). Multiple regression analysis showed that only age and vaccination status were significant predictors of antibody titres. The presence of antibody in all dogs suggests that the CPV infection is ubiquitous and the disease is endemic, hence the need for research to determine the protection conferred by vaccination and natural exposure to the virus under local conditions.

Risk Factors for Infection with Soil Transmitted Helminths, Cryptosporidium spp., and Giardia duodenalis in Children Enrolled in Preschools in Kafue District, Zambia

Intestinal parasitic infections are common among children worldwide. This study was aimed at determining risk factors for infection with soil transmitted helminths, Cryptosporidium spp., and Giardia duodenalis, among children in preschools. The study was in two parts: a cross-sectional study in which data were collected from 403 children from 10 preschools and a longitudinal study in which 100 children from four preschools from the previous 10 were selected. Prevalence of Ascaris lumbricoides was 12.0%, while that of hookworm was 8.3%. Overall prevalence of Cryptosporidium and G. duodenalis was 28.0% and 29.0%, respectively. Low education level of parent/guardian was a significant risk factor for A. lumbricoides (OR = 2.35, 95% CI: 1.02–5.41; ), while roofing types other than corrugated iron sheets were found to be protective for G. duodenalis infection in both bivariate and multivariate analyses (multivariate: OR = 0.67, 95% CI: 0.45–0.99; ). Low socioeconomic level was found to be protective for Cryptosporidium spp. infection in multivariate analysis (OR = 0.59, 95% CI: 0.35–0.99; ). In the longitudinal study, none of the factors were associated with either infection. These findings may have implications for other preschools in other districts in Zambia.

Prevalence of Cryptosporidium spp. oocysts in dogs in Lusaka district of Zambia

Aim: Cryptosporidium is one of the causes of diarrheal illness in man and animals worldwide and is zoonotic. The study aimed to determine the prevalence and risk factors associated with fecal shedding of Cryptosporidium oocysts in dogs in Lusaka district of Zambia. Materials and Methods: A cross-sectional study was conducted in Lusaka district of Zambia during 2015-2016. A total of 390 dogs (243 males and 147 females) aged 2 months-13 years were enrolled. Fecal samples were collected and stained using modified Ziehl-Neelsen and Auramine O staining techniques and examined microscopically for oocysts. Results: Overall, the prevalence of Cryptosporidium oocysts infection was 5.9% (23/390; 95% confidence interval: 3.9-8.7). Prevalence among male dogs and female dogs was 5.3% and 6.8%, respectively. Older dogs had a relatively higher infection rate compared to the younger puppies. There was a statistically significant difference in infection between nondescript breed and pure breeds with prevalence being higher in nondescript dog breeds. Water source was also significantly associated with Cryptosporidium infection. Conclusion: Cryptosporidium infections are common, especially among the nondescript breed of domestic dogs in Lusaka district of Zambia. Further studies to characterize the common species are warranted.