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

Risk factors and economic losses associated with cystic echinococcosis among livestock in selected pastoral and agro-pastoral areas of Uganda

BACKGROUND

Cystic echinococcosis is a parasitic cyclo-zoonotic disease caused by the taeniid Echinococcus and causes significant economic losses in livestock production, yet its impact is often overlooked and under estimated.

METHODS

This study investigated the risk factors and economic impact of cystic echinococcosis in livestock, in Uganda's pastoral and agro-pastoral communities. In the study, 14,937 livestock were examined at selected slaughterhouses in Moroto, Kumi, Luwero and Nakasongola districts from March 2019 to February 2020. The visceral organs were examined for hydatid cysts during slaughter and the prevalence correlated with the risk factors got from livestock traders and livestock owners through questionnaire survey. Production losses and economic losses due to organ condemnations were also estimated.

RESULTS

This is the first study to provide insights into the financial impacts and risk factors towards Cystic Echinococcosis (CE) in livestock in Uganda. The key significant risk factors for the persistence of CE in goats were place of origin from Lira (P ≤ 0.000), Nakasongola (P ≤ 0.002), Luwero and Bukedea (P ≤ 0.002), and tethering (P ≤ 0.001); in cattle was communal grazing (P ≤ 0.0000); and in sheep was being kept in large flocks (P ≤ 0.004). The total annual economic losses due to CE on livestock inspected in abattoirs in the study districts was USD 21,352.7 (1 USD = 3,809.3 UGX) of which 11.7% was due to organ condemnation and 88.3% due to livestock production losses. More significant mean annual economic losses per livestock species examined occurred in Moroto district among Zebu cattle USD 8.4, goats USD 1.4 and sheep USD 1.4 than other districts.

CONCLUSION

Results show that CE is a disease of significant economic and public health importance in PAP areas in Uganda with urgent need to create awareness and institute community-based control measures involving multistakeholder particiapation.to break livestock-dog cycle.

Leading report regarding the molecular epidemiology of Taenia hydatigena from Pakistan and global overview of the genetic diversity and population structure of the parasite

Cysticercosis, caused by larval stage of Taenia (T.) hydatigena is a disease of veterinary concern which causes major economic losses in livestock sector globally. Although livestock is the most productive part of Pakistan's economy, the epidemiological prevalence and genetic diversity of T. hydatigena has not been studied in great detail. Current study was undertaken for the estimation of the prevalence and genetic diversity of T. hydatigena among the goats and sheep of Multan in South Punjab, Pakistan. A PCR protocol targeting the cytochrome c oxidase subunit 1 (cox1) gene of T. hydatigena revealed an overall prevalence of 31.33 % among the small ruminants with higher prevalence in females (40.86 %) and older age group of >3-≤5 years (40.74 %). A total of 30 isolates were sequenced for partial mitochondrial cox1 gene which yielded 12 haplotypes with a haplotype diversity of 0.798 ± 0.68 and nucleotide diversity of 0.0046 ± 0.00183. A star like configuration was demonstrated in the haplotype network with a centrally positioned haplotype. Neutrality indices like Tajima's D and Fu's Fs were also biased towards negativity, a characteristic which suggests an expanding parasitic population. Moreover, the genetic diversity of T. hydatigena was also computed for the partial cox1 gene sequences available on GenBank, NCBI. A total of 415 sequences were retrieved out of which 142 haplotypes were identified having a haplotype diversity of 0.9150 ± 0.012 coupled with a nucleotide diversity of 0.00830 ± 0.00043. The haplotype profile of T. hydatigena population displayed an absence of a central haplotype, however, considerable genetic variation was ascertained. All the populations except Africa had a high haplotype diversity (>0.9), however, high Fst values were observed for a few populations which elucidated limited gene flow among the populations of Central/East Asia, Middle East, Europe and South Asia.

Environmental contamination with feces of free-roaming dogs and the risk of transmission of Echinococcus and Taenia species in urban regions of southeastern Iran

BACKGROUND

Dogs are the most important definitive hosts of zoonotic taeniid helminths worldwide. Different Echinococcus and Taenia species of domestic and wild carnivores pose a potential risk to human population. High populations of free-roaming dogs (FRDs) in urban areas of Iran and widespread contamination of the environment with dog feces is a potential source of infecting people living in the urban regions with cystic echinococcosis (CE). Our knowledge on the risk of CE transmission in the urban settings in the endemic regions is limited. The present study surveyed the species and genotypes of E. granulosus sensu lato and other taeniids by examining feces of free-roaming dogs in the urban areas in the city of Kerman, southeastern Iran.

METHODS

The city was divided into 100 consecutive blocks of which 25 blocks were randomly selected. Fecal samples of FRDs were counted, mapped and fresh samples were collected. Then Zinc chloride flotation, and sequential sieving was performed, and the samples were examined under an inverted microscope. Single individual taeniid eggs were isolated, partial nad1 gene was amplified and sequenced to identify species and genotypes.

RESULTS

In total 5607 fecal samples of dogs were mapped and 83 fresh samples were collected. Taeniid eggs were detected in nine fecal samples (10.8%) from seven out of the 25 city blocks (28.0%). Echinococcus eggs were found in four samples (4.8%) from three city blocks, two samples containing E. granulosus sensu stricto (2.4%), two samples containing E. canadensis G6/7 (2.4%). In addition, three samples contained eggs of Taenia hydatigena (3.6%), and one sample of Taenia serialis (1.2%).

CONCLUSIONS

This study documented the potential risk of CE transmission to humans resulting from the feces of dogs roaming freely in urban areas.

Genetic diversity and haplotypes of Cysticercus tenuicollis isolates from slaughtered sheep and goats in Elazig and Bingol provinces of Turkey

BACKGROUND

The cestode Taenia hydatigena uses canids, primarily dogs, as definitive hosts, whereas the metacestode larval stage cysticercus infects a range of intermediate hosts, including domestic animals such as goats, sheep and pigs.

OBJECTIVES

In this study, we aimed to determine the genetic differences and haplotypes of Cysticercus tenuicollis isolates obtained from sheep and goats slaughtered in the Bingol and Elazig provinces of Turkey.

METHODS

C. tenuicollis isolates were collected from 44 sheep and 26 goats slaughtered in slaughterhouses in Bingol and Elazig. After the isolation of total genomic DNA from C. tenuicollis isolates, the genetic characterization of the partial mitochondrial cytochrome oxidase 1 (CO1) gene region (866 bp) was amplified using specific primers by polymerase chain reaction (PCR), the products were then sequenced, and haplotype and genetic diversity analyses were carried out.

RESULTS

As a result of the haplotype network analyses, 34 different haplotypes were detected around the main haplotype (Hap02) arranged in a star-like configuration and separated from other haplotypes by 1-28 mutation steps and covering 22.85% (16/70) of all isolates. Twenty-seven polymorphic fields were detected, 77.77% (21/27) of which were parsimony-informative, and secondary haplotype and nucleotide diversity were observed. Additionally, we detected high intraspecies haplotype diversity (hd: 0.933) and high nucleotide diversity (π: 0.00383), with 27 different nucleotide variation positions among the haplotypes of the isolates. Tajima's D value was negative, indicating population expansion and/or selection purification. The significantly negative Fu's Fs values indicated recent population expansion or the presence of expected rare haplotypes.

CONCLUSION

The results of this study confirmed that C. tenuicollis isolates clustered in one lineage and were closely related to the relevant reference sequences in different countries, confirming the circulation of C. tenuicollis in different geographical regions.

Visceral cysticercosis in a Kunekune sow: description and molecular identification of Taenia hydatigena

A 2-year-old Kunekune sow was submitted for necropsy following death after peritonitis and sepsis. In addition to peritonitis, numerous fluid-filled cysts were identified in the mesentery and hepatic parenchyma, which contained an approximately 1 cm metacestode (cysticercosis). Subsequent molecular characterization confirmed the presence of Taenia hydatigena, a non-zoonotic cestode species. To our knowledge, visceral cysticercosis caused by T. hydatigena has not been previously documented in Kunekune pigs. Taenia solium is a differential diagnosis of public health importance in cases of cysticercosis. Although Taenia solium is not commonly reported nor endemic in the United States, its zoonotic potential warrants consideration in the initial diagnostic assessment. Clinicians should be aware of the presence of T. hydatigena in its definitive and intermediate hosts.

Prevalence of cystic echinococcosis among livestock in pastoral and agro-pastoral areas in Uganda

Cystic echinococcosis (CE) remains a significant challenge in Uganda with precise status largely undocumented in most communities. To determine CE prevalence, post-mortem examination was done on 14 937 livestock (5873 goats, 1377 sheep, 3726 zebu cattle and 3054 Ankole cattle) slaughtered in abattoirs in the districts of Moroto in Karamoja region, Kumi in Teso region and Nakasongola and Luwero in Buganda region. The overall CE prevalence was 21.9% in sheep, 15.2% in zebu cattle, 5.5% in goats and 2.1% in Ankole cattle. Moroto district had a higher prevalence of CE than other districts with 31.3% in zebu cattle, sheep 28%, goats 29.1% and (0%) in Ankole cattle. On organ locations, the lungs were the most affected in all livestock in all the study areas. Considering cyst fertility, 33.9, 1.7 and 6.4% of Ankole cattle, sheep and zebu cattle respectively had fertile cysts in the liver while 4.5% of goats and 4% Ankole cattle had fertile cysts in the lungs. In conclusion, CE is widespread and occurs among cattle, sheep and goats in pastoral and agro-pastoral areas in Uganda. Therefore, there is an urgent need to create awareness among the communities on role of livestock in CE epidemiology and transmission.

A rare case of Cysticercus tenuicollis infection in a neonate lamb: Evidence of prenatal transmission

Cysticercosis develops in lambs following a Cysticercus tenuicollis infestation, which is the larval stage of Taenia hydatigena. A 7-day-old lamb was examined for depression, anorexia, fever (40.5°C), congested mucus membranes, reluctance to move, and a hunched back. Upon necropsy, congestion was noted in the intestines and brain, and the heart had a loose consistency. Soft and pulpy kidneys were evident coupled with watery intestinal contents. Epsilon toxin (Clostridium perfringens type D toxin) was detected using enzyme-linked immunosorbent assay. A transparent cystic structure was incidentally found attached to the pancreas, within which a scolex was well demonstrated upon histopathology. Chronic active peritonitis was diagnosed at the cyst attachment site. C. tenuicollis was confirmed by polymerase chain reaction and genome sequencing. This report describes prenatal transmission of C. tenuicollis in the present lamb, although this condition is quite rare.

Gastrointestinal Parasites of Dogs in Egypt: An Update on the Prevalence in Dakahlia Governorate and a Meta-Analysis for the Published Data from the Country

Since the last survey on gastrointestinal (GIT) parasites infecting dogs in Dakahlia governorate, Egypt, was published 40 years ago, the present study detected various GIT parasites in feces of 78 stray dogs in this governorate. Twenty-one dogs (35.9%) had eggs/oocysts of eight different parasites including Toxocara canis (19.2%), Toxascaris leonina (2.6%), hookworms (1.3%), Taenia species (5.1%), Dipylidium caninum (2.6%), Cystoisospora canis (5.1%), Cystoisospora ohioensis (2.6%), and Neospora caninum-like oocysts (1.3%). These results were combined in various meta-analyses with findings of all published surveys on GIT parasites of dogs in Egypt to underline the potential parasitic zoonoses from dogs in the country. Feces and/or gastrointestinal tracts of 19,807 dogs from various Egyptian governorates, but particularly Cairo, have been microscopically tested in 182 datasets published between 1938 and 2022, revealed during our systematic database search. Toxocara canis, interestingly, displayed a twofold higher pooled prevalence (24.7%) when compared to the published global pooled prevalence for T. canis, indicating that dogs represent a major risk for toxocariasis in humans from Egypt. Dipylidium caninum (25.4%) as well as various Taenia species (17.1%) also displayed high pooled prevalences. On the contrary, lower pooled prevalence was estimated for the most important zoonotic taeniid "Echinococcus granulosus" (2.4%) as well as for hookworms (1.8%) in comparison to what has been published from other countries in the region. Relatively high prevalences were estimated for three protozoa detected in dogs and are common to infect children in Egypt; Cryptosporidium (5.5%), Giardia (7.4%), and Entamoeba histolytica (9.8%). In general, the pooled prevalence estimated for various parasites detected in dogs from Egypt has decreased in the recent years, sometimes by as much as one-fifth, but this great decline is statistically insignificant, which should alert the veterinary and public health authorities to continue their efforts for controlling these parasites in a "One Health" approach.

Global epidemiology and molecular biology of Taenia multiceps: a comparative meta-analysis and in silico analysis study

In the present study, all published data on the epidemiology and molecular characters of Taenia multiceps were systematically collected from relevant databases (e.g. PubMed, Scopus, National Center for Biotechnology Information), and combined in various statistical and genetic analyses as a contribution to a better understanding of the epidemiology of this ubiquitous taeniid worldwide. While 5.8% of the key hosts (dogs) from various countries had T. multiceps, grey wolves displayed the highest prevalence (21.6%) among the definitive hosts. Small ruminants are the main intermediate hosts and carry the coenuri in various locations, but most commonly in the central nervous system (CNS). Cerebral coenuri were confirmed in 53% of sheep exhibiting neurological symptoms, and infected animals often had only a single coenurus in the brain. Sheep had a higher prevalence (8.8%) of CNS coenuri than goats (5.8%); however, extra-CNS coenuri were detected more frequently in goats than in sheep. In either case, the difference between sheep and goats was statistically insignificant. Analysis of 233 partial cytochrome oxidase subunit I nucleotide sections for T. multiceps revealed high haplotype and low nucleotide diversities. Fifty-one haplotypes were detected circulating in 6 geographic populations. China, Iran and Turkey had 2 major haplotypes, whereas Italy and Egypt shared 3. Haplotypes from Greece circulate worldwide, and displayed similar gene flow values when compared with the other populations. There were no distinct patterns for haplotype distribution in relation to the infected hosts or coenuri locations. The existence of genetic variants in T. multiceps was highlighted, but needs further studies.

Comparison of mitochondrial genetic variation of Taenia hydatigena cysticerci from China and Mongolia

Parasitic infection is one of the many challenges facing livestock production globally. Cysticercosis tenuicollis is a common parasitic disease in domestic and wild ruminants (intermediate host) caused by the larval stage of Taenia hydatigena that primarily infects dogs (definitive host). Although genetic studies on this parasite exist, only a few describe the genetic variation of this parasite in Mongolia. Our aim was thus, to identify the mitochondrial differences in ovine isolates of Cysticercus tenuicollis entering China from Mongolia and comparison with existing Chinese isolates from sheep and goats based on the recently described PCR-RFLP method and mitochondrial genes of NADH dehydrogenase subunit 4 (nad4) and the NADH dehydrogenase subunit 5 (nad5). Sixty-nine isolates were collected during routine veterinary meat inspections from sheep that originated from Mongolia, at the modern slaughterhouses in Erenhot City, Inner Mongolia. Additional 114 cysticerci were also retrieved from sheep and goats from northern (Inner Mongolia Autonomous Region, Ningxia Hui Autonomous Region, and Gansu Province), western (Tibet Autonomous Region), and southern (Jiangxi Province and Guangxi Province) China. The PCR-RFLP approach of the nad5 showed nine mitochondrial subclusters A1, A2, A3, A5, A8, A9, A10, A11, and B of T. hydatigena isolates from sheep and goats from Mongolia and China. Meanwhile, haplogroup A1 RFLP profile was more widespread than other variants. These data supplements existing information on the molecular epidemiology of T. hydatigena in China and Mongolia and demonstrate the occurrence of similar genetic population structures in both countries.

Prevalence and phylogeography of Taenia hydatigena metacestodes from goats of India

The study determined the prevalence and genetic population structure relationships of Cysticercus tenuicollis (Taenia hydatigena metacestode) retrieved from the goats slaughtered in north India. An overall prevalence of 9.62% (59/613) was recorded. Genetic population structure relationships were assessed by targeting partial cytochrome c oxidase subunit 1 mitochondrial gene sequence. Phylogenetic tree analysis revealed that all the present study representative isolates (n = 7) formed a major clade and grouped with T. hydatigena isolates retrieved from sheep, goats, pigs and dogs, originating from China, Iran, Nigeria, Ghana and Poland. However, a single isolate from Himachal Pradesh (isolate 3) formed a subgroup within the clade. The neutrality and diversity indices revealed high values of haplotype diversity [Hd = 0.99695 (0.95238–1.0000)] and low nucleotide diversity (π = 0.49276), which was indicative of demographic expansion and low gene flow, suggesting that Indian T. hydatigena isolates were not genetically differentiated. Tajima's D (−1.26988) and Fu and Li's D statistics values (−0.74556) were negative, demonstrating deviations from neutrality and both propounded recent population expansion or purifying selection. Results highlighted a low genetic diversity of T. hydatigena metacestodes across the geographical range of north India.

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.