Intestinal helminths of stray dogs from Tunisia with special reference to zoonotic infections

Prevalence, risk factors and zoonotic potential of intestinal parasites in dogs from four locations in Morocco

Dogs can harbor various intestinal parasites that have serious clinical, economic, and zoonotic impact. In Morocco, the epidemiological status of those parasites is largely unknown. This study aimed to obtain data on the prevalence of intestinal parasites in various Moroccan dog populations, to identify associated risk factors, to evaluate people's knowledge regarding zoonotic parasites and to estimate the risk of human infection. A total of 291 fecal samples were analyzed using a 33% Zinc Sulphate (ZnSO4) centrifugal flotation and a sheather's sugar simple flotation techniques. In addition, 100 dog owners were asked to fill out a questionnaire about their knowledge regarding canine zoonotic intestinal parasites. Overall, 58% of sampled dogs were positive for at least one parasite species. Ancylostoma/Uncinaria spp. (31.9%), Toxascaris leonina (27.4%), Toxocara canis (27.1%), Cystoisospora spp. (13.4%) and Giardia spp. (7.2%) were the most frequently isolated parasites. The overall prevalence was associated with the dogs' activity, and feces consistency. More specifically, the prevalence of Ancylostoma/Uncinaria spp., Toxascaris leonina and Cystoisospora spp. was associated with dogs' activity and feces consistency and, additionally with age for Cystoisosporaspp.Toxocara canis prevalence was associated with age and feces consistency, while Giardia spp. prevalence was associated with dogs' activity. A weak awareness among dog owners regarding the zoonotic potential of canine intestinal parasites was noticed (33%) especially when their knowledge was compared to another endemic zoonotic disease, i.e. rabies (85%). Furthermore, the rate of respecting the vaccination protocol (82%) was significantly higher than the rate of respecting the deworming protocol (47%). We conclude that intestinal parasites, including the zoonotic ones, were highly prevalent in the dogs sampled in this study whereas people's knowledge about those parasites was very limited. These findings suggest that the risk of human infection is very likely, which highlights the need for effective control programs and health education.

Molecular identification of Taenia hydatigena from domestic and free-living animals in Slovakia, Central Europe

Taenia hydatigena is a cosmopolitan tapeworm that uses canids or felines as definitive hosts, while the larval stage (metacestode), formerly referred to as cysticercus tenuicollis, infects a wide variety of intermediate hosts, in particular ruminants. In the present study, we used partial nucleotide sequences of the cox1 and nad1 genes of T. hydatigena from different animal species to analyse the intraspecies genetic diversity of this economically important parasite. Twenty-four samples of metacestodes or adults of T. hydatigena from infected sheep, chamois, roe deer, fallow deer, wild boar, and dogs from Slovakia were collected and further analysed. Several haplotypes of T. hydatigena were identified with unique mutations that have not been previously recorded in Slovakia. Analysis of nucleotide polymorphism revealed the existence of 9 and 13 haplotypes, with relatively low nucleotide pairwise divergence ranging between 0.3-1.3 and 0.2-1.8% for the Hcox and Hnad haplotypes, respectively. In general, low nucleotide and high haplotype diversities in the overall population of T. hydatigena from the study indicate a high number of closely related haplotypes within the explored population; nucleotide diversity per site was low for cox1 (Pi = 0.00540) and slightly higher for nad1 (Pi = 0.00898). A molecular study confirmed the existence of genetic variation within T. hydatigena isolates from Slovakia. However, further investigations with more samples collected from different intermediate and definitive hosts are required in order to investigate the epidemiological significance of the apparent genetic differences observed in this study.

Owned and free-roaming dogs in the North West of Tunisia: estimation, characteristics and application for the control of dog rabies

Understanding the structure of dog population and the evaluation of the accessibility of dogs to vaccination is essential to succeed in the fight against dog rabies and to adapt the strategy of its control. We studied the characteristics of the unowned and owned dogs using the beck method during a rabies vaccination campaign in randomly selected sectors (urban and rural sites) in the North West of Tunisia. During a door-to-door investigation of households, data on owned dogs were collected to describe the owned population dog. A photographic-recapture method was used to characterize and estimate the size of the unowned dogs. A total of 1432 households accounting for 5403 inhabitants were interviewed during the survey (1298 (90.6%) in the urban site and 134 (9.3%) in the rural site). The dog-owning households were significantly higher in the rural site (76.1% (102/134)) compared to the urban site (17.8% (231/1298)) (P < 0.000000). Of the 17.8% dog-owning households in urban site, 58.4% owned one dog and 9% between 4 and 8 dogs. While, of the 76.1% dog-owning households in rural site, 24.5% owned one dog and 32.3% owned between 4 and 10 dogs. The dog: human ratio was 1:11 in the urban site and 1:1.6 in the rural site. The dog population density was estimated at 16 dogs/km2 and 4 dogs/km2 in the urban and rural sites, respectively. The confinement practices varied significantly among the urban and rural sites (P < 0.000000). The percentage of free-roaming owned dogs was 51.1% in the rural site and 31.4% in the urban site. More than 60.0% of the owned dogs in the urban site were confined. The majority of dogs in the rural site were born in the house, although, a high percentage (56.7%) of owned dogs in the urban site was adopted from neighbours, others sectors, or countries. The vaccination coverage findings indicated that 77.8% and 84.2% of the owned dog were vaccinated in the urban and rural sites, respectively. The estimated size of the free-roaming dogs was 72 dogs in the urban site (Kalaat Senan) and 16 dogs in the rural site (Sod el Khir).

Molecular characterization of Cysticercus tenuicollis isolates from sheep in the Nile Delta, Egypt and a review on Taenia hydatigena infections worldwide

The predator–prey-transmitted cestode Taenia hydatigena infects a wide range of definitive and intermediate hosts all over the world. Domestic and sylvatic cycles of transmission are considered as well. The parasite has considerable economic importance, particularly in sheep. Here, the molecular characters of T. hydatigena cysticerci in sheep from the Nile Delta, Egypt were investigated for the first time. For this purpose, 200 sheep carcasses and their offal were inspected at the municipal abattoir, Dakahlia governorate, Egypt. Cysticerci of T. hydatigena were collected and molecularly characterized employing the mitochondrial 12S rRNA gene. Cysticerci were found in 42 (21%) sheep, mostly attached to the omenti, mesenteries and livers. After molecular confirmation, nine isolates were sequenced displaying six different haplotypes. Analysis of the T. hydatigena 12S rRNA nucleotide sequences deposited in GenBank revealed 55 haplotypes out of 69 isolates, displaying high haplotype (0.797) and low nucleotide (0.00739) diversities. For the Tajima D neutrality index, a negative value (−2.702) was determined, indicating the population expansion of the parasite. Additionally, global data summarized in this study should be useful to set up effective control strategies against this ubiquitous parasite.

Human and animal cystic echinococcosis in Tataouine governorate: hypoendemic area in a hyperendemic country, myth or reality?

BACKGROUND

Cystic echinococcosis (CE) has a worldwide distribution and is especially prevalent in North African countries. With a mean annual surgical incidence (ASI) of CE of 12.7 per 100,000 inhabitants, Tunisia is one of the most CE endemic countries in the Mediterranean area. Tataouine governorate is considered to be the most CE hypoendemic region in Tunisia (ASI = 0.92) despite favourable socioeconomic conditions that enable maintenance of the Echinococcus granulosus sensu lato (s.l.) life-cycle and a significant environmental contamination with E. granulosus s.l. eggs. The aim of this study was to assess human CE seroprevalence, prevalence of CE in food animals and environmental contamination by E. granulosus s.l. eggs in different districts of Tataouine governorate.

METHODS

This study was conducted from January to December 2018. A total of 374 human sera samples were tested for the presence of immunoglobulin G antibodies against E. granulosus using a commercial ELISA kit. Specimens were also collected from animals slaughtered at the Tataouine abattoir (n = 8609) and examined for the presence of hydatid cysts; 111 hydatid cysts were genotyped. Eggs of E. granulosus s.l. were identified by PCR and DNA sequencing from dog faecal samples (n = 288).

RESULTS

Serological tests showed that 8.5% of the sera samples tested were positive for E. granulosus-specific antibodies. The average prevalence of hydatidosis in livestock was 1.6%, and CE infection was more prevalent in cattle than in sheep, goats and dromedaries. The contamination rate of dog faeces by E. granulosus sensu stricto eggs varied significantly from 0 to 23.5% depending on the collection area. Molecular analyses only revealed the presence of the G1 genotype for cysts and eggs.

CONCLUSIONS

Based on our findings, CE is likely to be more endemic in the Tataouine governorate than previously described. Thus, to implement an effective control programme against CE, a national survey should be carried out to determine human CE prevalence in the different Tunisian governorates.

Parasitological Contamination of Vegetables Sold in Tunisian Retail Markets with Helminth Eggs and Protozoan Cysts

ABSTRACT

Foodborne diseases continue to represent an important threat to public health in many parts of the world and are particularly widespread in developing countries. They are essentially acquired through an oro-fecal route via the consumption of uncooked fruits and vegetables. This study evaluated the parasitological contamination of vegetables for sale to humans in Tunisian retail markets. A total of 240 samples of fresh vegetables were examined for helminth eggs and protozoan cysts and oocysts (collectively, (oo)cysts) contamination. The parasitic elements (helminth eggs and protozoan (oo)cysts) were concentrated by sucrose flotation and identified by microscopic examination. The molecular identification of Echinococcus granulosus eggs was carried out using PCR. Helminth eggs and protozoan (oo)cysts eggs were found in 12.5% of the unwashed vegetables, and the most common parasites observed in vegetables were coccidian oocysts (4.1%), Toxocara spp. (2.5%), hookworm (2.1%), and Taenia spp. (1.25%) eggs, followed by Pseudolimax butschlii (1.6%) and Entamoeba coli (1.6%) protozoan cysts. Furthermore, parasite contamination differed significantly from one city to another. Taeniid eggs were identified by PCR as E. granulosus sensu stricto (s.s.) (genotype G1). To our knowledge, this study highlights for the first time in Tunisia that fresh vegetables for sale in markets are contaminated with helminths and protozoan cysts, which are potentially pathogenic for humans. The control of these pathogens is in part a question of sanitary education, especially for retail vendors, and in part of improvement in hygiene measures throughout the food production chain, from the field to the consumer.

HIGHLIGHTS

Prevalence of Toxocara in dogs and cats in Africa

Dogs and cats have a close association with humans providing companionship; however, pets are reservoirs of zoonotic pathogens such as Toxocara. Toxocara canis and Toxocara cati are small intestinal nematodes found in canids and felids, respectively. Infected pets shed thousands of eggs resulting in environmental contamination. Toxocara can infect a wide variety of paratenic hosts including humans, rodents, pigs and chickens. Paratenic hosts become infected by ingestion of the infective eggs containing the third stage larvae or ingestion of dormant larvae in animal tissues. Infected humans may develop visceral larval migrans or ocular toxocariasis. Regular anthelmintic treatment and restricted movement of dogs and cats are recommended to control Toxocara environmental contamination. This paper reviews the prevalence and risk factors of Toxocara in dogs and cats in Africa; and pet owners' awareness of canine zoonotic helminths.

Prevalence of Intestinal Helminth Infections of Stray Dogs of Public Health Significance in Lagos Metropolis, Nigeria

Globally, stray dogs have been a major source of zoonoses such as cutaneous larval migrans, visceral larval migrans and hydatidosis. These dogs are recognized as being a major public health problem where their population is unchecked. This study was conducted to determine the prevalence of intestinal helminth parasites of stray dogs in Lagos metropolis. Stools of 96 stray dogs were examined microscopically for ova of these parasites using centrifugation flotation method. Four species of intestinal helminths were identified. The overall prevalence of helminths infection was 61.4%, with Ancylostoma caninum having a prevalence of 62.5%, Toxocara canis 20.8%, Dipylidium caninum 18.7% and Strongyloides stercoralis 2.0%. T. canis had the highest worm burden of 1,250 egg per gram (EPG) while S. stercoralis had the least (100 EPG). The areas with the most helminth infections were Yaba (n=12, X̄=1.58, SD=0.793), Agege (n=11, X̄=1.73, SD=0.786) and Ikotun (n=11, X̄=1.45, SD=0.820). S. stercoralis was only found in samples obtained from Mushin and Ikorodu. Most of the stool samples obtained from this study had mixed infections, 83.3% were infected with three helminth species, 8.3% were infected with four helminth species and none had double infection. Mushin had the most mixed infections (n=4, X̄=1.900, SD=1.101) while Obalende had the least (n=1, X̄=1.000, SD=0.000). Most of the intestinal helminth parasites identified in this study are zoonotic and thus pose a public health problem. Environmental factors seem to influence the health condition of these dogs, thus concerted efforts should be made to reduce the growing population of stray dogs on the street of Lagos.

Cystic echinococcosis and other helminth infections of wild boar in northeastern and northwestern regions of Tunisia

This study identified helminth species of wild boar (Sus scrofa) originating from northeastern and northwestern regions of Tunisia using 297 lungs, 297 livers, 264 intestinal tracts, 120 samples of muscle tissue (tongue, masseter, diaphragm, inter-costal) and 232 faecal samples derived from a total of 591 animals. Host gender was registered for the lung and liver wild boar group, which included 163 males and 134 females. All animals, excluding those used to retrieve muscular samples, were classified into three age classes, <2 (n = 212), 2-3 (n = 208) and ⩾4 years old (n = 141). Helminth fauna of the examined wild boar included 14 parasite species: one trematode (adult, Brachylaemus suis), three cestodes (metacestodes of Echinococcus granulosus, Taenia hydatigena cysticercus, adult, Hymenolepis diminuta), nine nematodes (adults of Metastrongylus apri, Metastrongylus pudendotectus, Ascarops strongylina, Globocephalus urosubulatus, Physocephalus sexalatus, Gnathostoma hispidum, Gongylonema pulchrum and eggs of Strongyloides ransoni and Capillaria spp.) and one acanthocephalan (adult, Macracanthorhynchus hirudinaceus). Trichinella larvae were not recovered from any of the 30 wild boar examined. Results showed a 73.5% global prevalence of infection with visceral helminths, 67.3% of which were lung and hepatic infections and 80.3% of helminths were recovered from the gastrointestinal tract. The most prevalent parasite was M. hirudinaceus (61.7%) while the highest intensity of infection was observed for Metastrongylus spp. The most prevalent cestode was E. granulosus (18.9%). This is the first detailed study on helminth infections of wild boar from a North African country.

First Molecular Identification of Taenia hydatigena in Wild Ungulates in Poland

The article examines the presence of metacestodes on the liver capsule in two wild boars and on the liver capsule and mediastinum in moose. Cysticerci were identified as Taenia hydatigena metacestodes by morphological features-size and shape of rostellar hooks and molecular analysis of the partial sequences of cytochrome c oxidase subunit 1 gene. Molecular analysis revealed similarities between the metacestodes isolated from the wild mammals in the present study to T. hydatigena in European wolves. It is possible that infection of moose and wild boar with T. hydatigena metacestode is related to the growth in the wolf population in Europe.