Occurrence and factors associated with Cryptosporidium infection in livestock in three districts of Zambia.

Cryptosporidium is one of the most important enteric diarrhoeal parasites that infect humans and animals worldwide. The current study investigated the occurrence and risk factors associated with Cryptosporidium infection in ruminants aged ≤6 months in Monze, Mumbwa, and Lusaka districts of Zambia. Faecal samples were collected from 328 calves, 190 lambs, and 245 goat kids and analysed for Cryptosporidium oocysts using modified Ziehl Neelsen staining. A closed structured questionnaire was used to obtain epidemiological characteristics and potential risk factors for Cryptosporidium infection. The overall occurrence of Cryptosporidium was 7.9% (60/763), while that in calves, lambs and goat kids was 14.5% (47/328), 5.3% (10/190), and 1.2% (3/245) respectively. Watery/pasty stool and sampling during the rainy season were independently associated with increased risk of infection. In calves, the odds of infection increased during the rainy season, while daily kraal cleaning reduced the infection risk. Lambs showed increased odds of infection with pasty/watery stool and male sex, whereas the wearing of protective clothing by handlers significantly reduced the risk. There were district variations in infection occurrence with Mumbwa district having higher prevalence. The findings of this study show that livestock in Zambia continue to be frequently infected with Cryptosporidium. Protective measures and appropriate farm cleanliness should be implemented in control of this infection. Regional and host-species-specific variations emphasize the need for targeted interventions. These findings, therefore, contribute to effective strategies for Cryptosporidium control, promoting good livestock health and management.

Detection of Human Adenovirus and Rotavirus in Wastewater in Lusaka, Zambia: Demonstrating the Utility of Environmental Surveillance for the Community.

Enteric infections due to viral pathogens are a major public health concern. Detecting the risk areas requires a strong surveillance system for pathogenic viruses in sources such as wastewater. Towards building an environmental surveillance system in Zambia, we aimed to identify group A rotavirus (RVA) and human adenovirus (HAdV) in wastewater. Convenient sampling was conducted at four study sites every Tuesday for five consecutive weeks. The research team focused on three different methods of viral concentration to determine the suitability in terms of cost and applicability for a regular surveillance system: the bag-mediated filtration system (BMFS), polyethylene glycol-based (PEG) precipitation, and skimmed milk (SM) flocculation. We screened 20 wastewater samples for HAdV and RVA using quantitative polymerase chain reaction (qPCR) and conventional polymerase chain reaction (cPCR). Of the 20 samples tested using qPCR, 18/20 (90%) tested positive for HAdV and 14/20 (70%) tested positive for RVA. For the genetic sequencing, qPCR positives were subjected to cPCR, of which 12 positives were successfully amplified. The human adenovirus was identified with a nucleotide identity range of 98.48% to 99.53% compared with the reference genome from GenBank. The BMFS and SM flocculation were the most consistent viral concentration methods for HAdV and RVA, respectively. A statistical analysis of the positives showed that viral positivity differed by site (p < 0.001). SM and PEG may be the most appropriate options in resource-limited settings such as Zambia due to the lower costs associated with these concentration methods. The demonstration of HAdV and RVA detection in wastewater suggests the presence of the pathogens in the communities under study and the need to establish a routine wastewater surveillance system for the identification of pathogens.

Cryptosporidiosis is predominantly an urban, anthroponotic infectious disease among Zambian children.

BACKGROUND: Cryptosporidium species are leading causes of diarrhoea in children and immunocompromised individuals. This study aimed to characterise Cryptosporidium species from children in rural and urban settings of Zambia. METHODS: Stool samples collected from 490 children aged <5 y with diarrhoea were assessed for Cryptosporidium oocysts microscopically. A structured questionnaire was used to collect demographic and socioeconomic characteristics. Positive samples were subjected to PCR and gp60 sequence analysis. RESULTS: The overall prevalence was 10% (50/490, 95% CI 7.8 to 13.2) with a peak in March, the late rainy season. Children who came from households where boiling water was not practised (OR=2.5, 95% CI 1.29 to 5.17; p=0.007) or who had experienced recurrent episodes of diarrhoea (OR=9.31, 95% CI 3.02 to 28.73; p=0.001) were more likely to have Cryptosporidium infection. Genotyping of 16 positive samples (14 from urban and 2 from rural sources) revealed Cryptosporidium hominis (14/16) and Cryptosporidium parvum (2/16). The Cryptosporidium hominis subtypes identified were Ia, Ib and Ie with subtype families IeAIIG3 (1), IbA9G3R2 (2), IaA31R3 (3), IbA9G3 (5), IaA27R3 (1), IaA30R3 (1) and Ia (1). Subtypes IbA9G3 and Ia were identified in children from a rural area. Cryptosporidium parvum subtypes were IIcA5G3R2 (1) and IIcA5G3a (1). CONCLUSIONS: All isolates successfully genotyped were C. hominis or anthroponotic C. parvum, suggesting that anthroponotic transmission dominates in Lusaka and the surrounding countryside.

A One Health Approach to Child Stunting: Evidence and Research Agenda.

Stunting (low height for age) affects approximately one-quarter of children aged < 5 years worldwide. Given the limited impact of current interventions for stunting, new multisectoral evidence-based approaches are needed to decrease the burden of stunting in low- and middle-income countries (LMICs). Recognizing that the health of people, animals, and the environment are connected, we present the rationale and research agenda for considering a One Health approach to child stunting. We contend that a One Health strategy may uncover new approaches to tackling child stunting by addressing several interdependent factors that prevent children from thriving in LMICs, and that coordinated interventions among human health, animal health, and environmental health sectors may have a synergistic effect in stunting reduction.

Food and waterborne protozoan parasites: The African perspective.

Parasitic food-borne diseases, particularly those caused by the protozoan parasites Cryptosporidium, Giardia, Cyclospora cayetanensis and Entamoeba are increasingly becoming common and have received considerable attention in the last two decades. The ability of the transmission stages of the parasites to survive in the environment for prolonged periods, globalization of the food industry and changes in eating habits have contributed to the numbers of human infections. This systematic scoping review highlights these important water- and foodborne parasites in the African context, detailing the burden in African water sources, wastewater/effluents and fresh produce. A scoping review search targeting African countries was conducted in Medline, Web of science and African journals online as well as back referencing from included studies covering the period 1990 to January 2020. Out of 1134 studies, 68 were included in the review. The articles covered 17 out of 54 African countries. There were 39/68 studies reporting on water sources while the rest reported on fresh produce. Cryptosporidium prevalence ranged from 6 to 100% in surface water, 4 to 100% in tap water and up to 100% in wastewater and sludge. In fresh produce, Cryptosporidium was reported from five countries with prevalence of 0.8-75%. Giardia was reported in 47 out of 68 articles; prevalence ranged from 2.4% in surface water; 1% to over 70% in tap water; 28-100% in wastewater and 2% - 99% in fresh produce. Prevalence of Cyclospora cayetanensis was lower. Prevalence of Entamoeba was 78% in surface water; 100% in wastewater and up to 99% in fresh produce. This study finds that Africa is no exception to the risk presented by the subject parasites from water and/or food sources. Routine screening for these parasites particularly at household level and provision of adequate and safe drinking water would help to control the parasites.

Hirudiniasis in Cattle in Mpwapwa District, Dodoma Region of Tanzania.

Hirudiniasis is a condition caused by infestation by leeches. Despite the annoyance, clinical signs, and associated lesions caused by leeches in both humans and animals, the extent of the problem in Tanzania is not well elucidated. Individual animals and people become infested when they drink, bath, or walk through contaminated water sources. Leech infestations are more common in rural areas where water is scarce especially during the dry season. In this report, clinical cases of hirudiniasis in twenty-seven (27) cattle in Mpwapwa, Tanzania, are presented. The report further reviews the morphological features of leeches and creates awareness among the affected cattle farmers and the general public. A total of two hundred (200) live cattle were examined; out of these, 27 cattle had live leeches. There were, on average, 3-8 leeches per animal. Affected cattle had wounds on the gums, buccal mucosa, root of the tongue, and under the tongue with copious amounts of blood-stained frothy discharge. Further, the affected animals had respiratory distress and were rolling their tongues. The leeches were manually removed from all the affected cattle, with uneventful recovery. Laboratory examination revealed segmented, dorsal-ventral flattened, cylindrical parasites which had posterior and anterior suckers. The leech infestation was linked to drinking water from a pond which was suspected to be contaminated with "undescribed organisms" as indicated by the farmers. A follow-up was made and revealed no new cases and complete recovery of the affected animals. Hirudiniasis is one of the neglected diseases in humans and livestock and, therefore, requires integrated efforts especially in areas where water is scarce during the dry season. It is anticipated that this case report will stimulate interest and more studies in the subject matter to understand the extent of the problem and document the species and distribution of leeches in Tanzania.

Factors Associated With Cryptosporidium Infection Among Adult HIV Positive Population in Contact With Livestock in Namwala District, Zambia.

Cryptosporidium spp. is one of the leading causes of diarrhoeal disease globally. In Zambia, the burden of Cryptosporidium infection in the general human population is unknown and factors associated with it are unclear. A study was conducted to determine the prevalence of Cryptosporidium spp. and identify factors associated with its infection among Human Immunodeficiency Virus (HIV) positive individuals in contact with livestock in Namwala district of Zambia. Three hundred and twenty six stool samples were collected from HIV infected individuals presenting at local health centers in Namwala district of Zambia between August 2015 and June 2016. The Meriflour Cryptosporidium/Giardia test kit was used to test for presence of oocysts. Demographic information such as age and sex and information on hypothesized risk factors was collected using a structured questionnaire. Overall prevalence of Cryptosporidium infection was 9.5% (95% CI = 6.7-13.2%); 13.3% and 7.1% among male and female participants, respectively. Males were 2.5 times more likely to be infected than females whereas the divorced had higher odds of being infected (OR = 14.8). Participants who kept animals had a higher prevalence (11.4%) than those that did not (7.0%). Those that shared water with neighbors were 5.7 times more likely to be infected than those who did not. We conclude that Cryptosporidium infection is prevalent among HIV positive adults in Namwala district and infection is associated with sex, marital status and sharing water sources among neighbors. Community sensitization is required to create awareness and reduce human exposure to Cryptosporidium infection.

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.

Asymptomatic cryptosporidiosis in Zambian dairy farm workers and their household members.

The prevalence of Cryptosporidium and the possibility of zoonotic transmission on dairy farms were examined. Eighteen cases of cryptosporidiosis (prevalence 6%) were identified in 82 farm workers and 207 household members. Furthermore, 70 (34%) of 207 calf samples were positive. Based on the 70kDa heat shock protein and the 18S rDNA gene, Cryptosporidium parvum was identified in 75% of the positive farm workers and in 60% of the household members. Of the positive calves, 62% were infected with C. parvum, indicating a possible zoonotic transmission on these farms.

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 dog's 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.

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.

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 Knott's 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 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.

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.