Primary characterization of the immune responses in Tibetan pigs infected with Chinese Tibet isolate of Trichinella spiralis.

BACKGROUND: Trichinellosis, caused by Trichinella spiralis, is a serious foodborne parasitic zoonosis. Tibetan pig is an infrequent, endemic plateau pig species, mainly distributed in Tibet Plateau, China. Because of the free-range system, Tibetan pigs are at risk of infection with Trichinella. The present study aimed to primarily profile the characteristics of T. spiralis infection in Tibetan pigs, including IgG levels, larvae burdens, and cytokines. RESULTS: The immune responses to Chinese Tibet T. spiralis isolate infection in Tibetan pigs with different doses were investigated in a tracking duration of 49 days. The muscle larvae per gram (lpg) were evaluated at 105 days post-infection (dpi). The results showed that the mean larval number of T. spiralis in Tibetan pigs increased with infective dose, with average lpg values of 3.5, 50.4 and 115.6 for Tibetan pigs infected with 200, 2,000, and 20,000 muscle larvae (ML) of T. spiralis. The anti-Trichinella IgG increased with inoculum dose and dpi, and peaked at 49 dpi. The kinetics of cytokines in the sera was detected by microarray, including interferon-γ (IFN-γ), interleukin (IL)-1ß, IL-8, IL-12, IL-4, IL-6, IL-10, Granulocyte-macrophage Colony Stimulating Factor (GM-CSF), tumor necrosis factor (TNF)-α and transforming growth factor (TGF)-ß1. The Th1/Th2 mixed cytokines were detectable in all samples. Interleukin-12 demonstrated the highest concentration compared to other cytokines and peaked at 42 dpi. Almost all cytokines were maintained at a high level at 42 dpi. Additionally, we also report a Trichinella seropositive rate of 43.9 % (18 out of 41) from field samples of Tibetan pigs. CONCLUSIONS: The present study showed an increased Th1/Th2 mixed cytokines in Tibetan pigs elicited by T. spiralis. The high seroprevalence of Trichinella infection in field samples of Tibetan pigs further raises serious concern for the prevention and control of trichinellosis in this host for public health safety.

Prevalence and distribution of Echinococcus spp. in wild and domestic animals across Africa: A systematic review and meta-analysis.

Cystic echinococcosis (CE), a worldwide zoonosis, is highly prevalent in Africa particularly in northern and eastern Africa where data are more abundant than other regions. However, harmonization of available data through systematic review and meta-analysis may foster improved transboundary cooperation for the control of CE in Africa. Using the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, research articles (from 2000 to 2019) were retrieved from ScienceDirect, PubMed, African Journals OnLine and Google Scholar databases. A total of 98 studies of 806,624 animals from 13 countries comprising 264,016 goats, 247,326 sheep, 251,106 cattle, 28,314 camels, 4,764 buffaloes, 2,920 equids, 1,966 pigs, 408 wild boars and 50 Norway rats were available for systematic review and meta-analysis of pooled prevalence including 5,048 dogs, 345 lions, 220 hyenas, 94 wolves and 47 jackals/foxes analysed for Echinococcus infection. In total, 46,869 animals were infected and pooled prevalence of CE in intermediate hosts was highest in camels (17.1%; 95% CI: 12.1-22.8) and lowest in pigs (0.3%; 95% CI: 0.1-0.6). Results also showed uneven species/genotype distribution across the continent such that Echinococcus granulosus sensu stricto (G1, G3) constituted 74.45% of the total isolates from East Africa, E. canadensis (G6/7) accounted for 60.3% and 97.4% in North and West Africa, respectively, while 81.3% of E. ortleppi (G5) were recorded for southern Africa. The comparatively higher prevalence estimates for eastern and northern Africa than other regions indicate where efforts on CE management should now be given greater attention in Africa. Additionally, this study also advocates for better cooperation between countries within the same sub-region and the establishment of joint CE control programmes.

First molecular description, phylogeny and genetic variation of Taenia hydatigena from Nigerian sheep and goats based on three mitochondrial genes.

BACKGROUND: Cysticercosis caused by the metacestode larval stage of Taenia hydatigena is a disease of veterinary and economic importance. A considerable level of genetic variation among isolates of different intermediate hosts and locations has been documented. Generally, data on the genetic population structure of T. hydatigena is scanty and lacking in Nigeria. Meanwhile, similar findings in other cestodes like Echinococcus spp. have been found to be of epidemiological importance. Our aim, therefore, was to characterize and compare the genetic diversity of T. hydatigena population in Nigeria based on three mitochondrial DNA markers as well as to assess the phylogenetic relationship with populations from other geographical regions. METHODS: In the present study, we described the genetic variation and diversity of T. hydatigena isolates from Nigerian sheep and goats using three full-length mitochondrial genes: the cytochrome c oxidase subunit 1 (cox1), NADH dehydrogenase subunit 1 (nad1), and NADH dehydrogenase subunit 5 (nad5). RESULTS: The median-joining network of concatenated cox1-nad1-nad5 sequences indicated that T. hydatigena metacestodes of sheep origin were genetically distinct from those obtained in goats and this was supported by high FST values of nad1, cox1, and concatenated cox1-nad1-nad5 sequences. Genetic variation was also found to be higher in isolates from goats than from sheep. CONCLUSIONS: To the best of our knowledge, the present study described the genetic variation of T. hydatigena population for the first time in Nigeria using full-length mitochondrial genes and suggests the existence of host-specific variants. The population indices of the different DNA markers suggest that analysis of long mitochondrial DNA fragments may provide more information on the molecular ecology of T. hydatigena. We recommend that future studies employ long mitochondrial DNA sequence in order to provide reliable data that would explain the extent of genetic variation in different hosts/locations and the biological and epidemiological significance.