Bangladesh, one of the top fish-producing countries in South Asia, has made significant progress in inland and marine fisheries and aquaculture in recent years. Parasitic infections in fish remain a major challenge and a threat to fish abundance and biodiversity. Fishes are affected by both external and internal parasites, with helminths being the most common. These parasites can affect fish growth, survival, and marketability and can pose a risk of fish-borne zoonosis. In recent years, global concern about food safety and security has remained high. Bangladesh is expanding its global fish and fish product exports, where fishbone parasites, particularly zoonotic helminths, are a major concern. But the occurrence and distribution of helminth parasites in Bangladeshi fish are not well documented due to lack of data. This study therefore aimed to gather and summarise the available data on helminth occurrence in fishes in Bangladesh using a systematic approach. Relevant articles were retrieved from five electronic databases/repositories, including PubMed, ProQuest, ScienceDirect, Scopus, and Google Scholar. A total of 55 articles were included in this review that reported helminth infections in 68 species of marine and inland fish, 50 families, and 96 genera of helminths, including acanthocephalans, cestodes, monogeneans, nematodes, and trematodes. Notably, 31 genera were considered to have zoonotic relevance. These findings suggest that collective measures should be taken, including implementing a parasitic disease control plan in aquaculture practices and raising public awareness about fishbone helminths in Bangladesh. Additionally, a collaborative approach should be adopted with neighbouring regions to combat this issue.
BACKGROUND:Canine vector-borne pathogens (CVBPs) cause a wide range of diseases. No studies have been performed on the prevalence of CVBPs in shelter dogs in Cyprus, despite the regular exporting of dogs from Cypriot shelters for rehoming. METHODS:From August 2017 to August 2019, a cross-sectional descriptive study was performed in dogs from three shelters in Cyprus. Quantitative PCRs for 'Candidatus Mycoplasma haematoparvum' (CMhp), Mycoplasma haemocanis, Leishmania spp. and Babesia spp. and conventional PCRs and sequencing for Ehrlichia/Anaplasma spp. and Hepatozoon spp. were performed on DNA extracted from EDTA blood samples. Multivariable logistic regression was performed to identify any risk factors associated with CVBPs PCR-positive status. RESULTS:Of samples collected from 145 dogs, eight were excluded from further analysis due to the presence of PCR inhibitors. Of the remaining 137, 76 (55.5%) were PCR-positive for at least one CVBPs, of which 21 dogs had more than one pathogen. The infections comprised 62/137 (45.3%) Hepatozoon canis, 14/137 (10.2%) Anaplasma platys, 13/137 (9.5%) M. haemocanis, 9/137 (6.6%) Leishmania spp., and 2/137 (1.5%) CMhp. All dogs tested negative for Babesia spp.. Regression analysis showed that positive-PCR status for A. platys was positively associated with the presence of ectoparasites, co-infection with H. canis, and the shelter being located in Paphos compared to the shelters in Nicosia, whilst age was positively associated with M. haemocanis positive-PCR status. CONCLUSIONS:The overall prevalence of CVBPs is high in Cypriot shelter dogs, including some with zoonotic potential. CVBPs pose a threat to the canine population in Cyprus, and further action is needed by local carers and veterinary authorities to contain their spread by limiting exportation or ensuring testing before travelling for export to avoid infection spread by the movement of dogs.
The aim of this study was to detect genomic regions and genes associated with gastrointestinal nematodes (GIN) resistance in Pelibuey sheep, based in deworming necessity (NOD) estimated by fecal egg count (FEC). During a ten-months period, deworming criterion was based on GIN eggs per gram (EPG), then animals exceeding 1000 EPG were dewormed, and individuals were classified as cases (dewormed at least once) or controls (non-deworming at all). Animals were genotyped with the GGP Ovine50k genome profiler microarray. Quality control of dataset and case-control GWAS were carried to identify associated candidate genes and quantitative trait loci (QTL). Two genome-wide strongly associated SNPs were detected on chromosomes 2 and 3, located near FEC associated QTLs and immune-related genes: GALNT6, KLRK1, KLRD1, CLEC1B, FGF13, TMEM52B, OLR1, and CLEC7A. The identified genes are involved in key defense mechanisms such as mucus synthesis, immune signaling, and natural-killer cell activation, supporting their relevance as candidate genes for GIN-resistance selection in Pelibuey hair-sheep.
Toxocara spp. are zoonotic parasites that cause toxocariasis in humans. In Vietnam, information on these parasites is fragmented, and many local reports remain inaccessible to the international research community. This study conducted a comprehensive literature review to assess the distribution and prevalence, and to estimate the true prevalence of Toxocara spp. in humans, dogs, and cats in Vietnam. The true prevalence was estimated using a Bayesian approach based on diagnostic test characteristics used in each published study. Of 766 studies screened, 58 studies were included in the systematic review and meta-analysis, including 109,597 humans, 8067 dogs, and 1034 cats. The pooled true prevalence was estimated at 38.5% (95% CI: 31.4-45.5) in humans, 42.3% (95% CI: 30.3-54.2) in dogs, and 50.1% (95% CI: 26.7-73.5) in cats. While numerous studies reported seroprevalence of Toxocara spp. antibodies in humans, data on Toxocara spp. in dogs and cats were limited. ELISA was employed in all included human studies to detect antibodies against Toxocara spp. larvae in humans, and the estimated true prevalence was largely consistent with the apparent prevalence, reflecting the test's assumed accuracy rather than definitive proof. Microscopic examination in dogs and cats likely underestimates the parasite prevalence due to limited sensitivity. The high prevalence of Toxocara spp. in dogs and cats highlights a significant public health concern, particularly given the inadequate management of dog and cat feces. These findings highlight the need for One Health strategies to control Toxocara spp. and reduce its burden in Vietnam.
Eustrongylides spp. are helminths with a multiple-host life cycle that can infect aquatic oligochaetes, various freshwater fish, fish-eating birds, and accidental mammalian hosts, including humans. This work aimed to morphologically and molecularly characterize the larval stages of Eustrongylides spp. isolated from European perch, and to outline the oxidative/nitrosative stress and histoarchitecture changes induced by active larval migration or tissue-encapsulation. Eighty Perca fluviatilis were collected from the Volga River (Astrakhan, Russia). Thirty-seven were tentatively grouped as infected based on the grossly visible Eustrongylides larvae in the oral cavity, gills, axial muscles, and internal viscera. The nematodes were examined microscopically and characterized at the molecular level by PCR amplification of nuclear small-subunit ribosomal RNA (nSSU-rRNA) gene fragments, followed by sequencing and phylogenetic analysis. Affected organs were evaluated for redox/ nitrosative status and histopathological tissue injury. Fifteen healthy fish were selected as controls. Morphological examination identified the isolated nematodes as Eustrongylides sp., which were subsequently identified as Eustrongylides excisus (E. excisus) by molecular analysis, contributing to an infection rate of 46.25% (37/80). E. excisus was identified based on 100% sequence identity with available GenBank references, although the 18S rRNA marker provides limited species-level identification. Our findings demonstrate that E. excisus infection triggers a significant shift in the host's oxidative and nitrosative burden. This oxidative-inflammatory response leads to marked pathological changes in affected organs, including blood vessel dilation, mononuclear cell infiltration, vacuolar degeneration, and necrosis. Ultimately, these larvae induce severe cellular damage in fish muscle and visceral organs, disrupting cellular integrity essential to normal physiological function.
