A PCR-RFLP assay for discrimination of Echinococcus granulosus sensu stricto and Taenia spp. in dogs stool

PCR-RFLP assay confirms the existence of different mitochondrial lineages of Taenia hydatigena including a possible geographically restricted group

Taenia hydatigena is a widespread tapeworm of canids (primarily dogs) that causes cysticercosis in ruminants (domestic and wild) and manifests as depression and weakness secondary to various hepatic damages and sometimes mortality in young animals, although, commonly encountered cases are asymptomatic. In most taeniids, genetic polymorphism has been found to impact host preferences, distribution, disease epidemiology and management. Recently, we identified two main mitochondrial lineages of T. hydatigena in China, and here, we examined the mitochondrial nad4-nad5 genes of T. hydatigena from China, Nigeria, Pakistan and Sudan to assess the intraspecies variation of isolates from these countries and also the distribution of the distinct mitochondrial groups. In addition to China, haplogroup B variant was found in Pakistan, while haplogroup A demonstrated a widespread distribution. We then designed a PCR-restriction fragment length polymorphism (PCR-RFLP) assay using XmiI (AccI) and RsaI (AfaI) restriction enzymes to differentiate members of both haplogroups. This result provides more molecular evidence supporting the existence of distinct mitochondrial variants of T. hydatigena. The epidemiological significance of these different mitochondrial groups remains to be explored further. The current PCR-RFLP assay offers a useful molecular approach for investigating the genetic population structure of T. hydatigena in enzootic regions and in identifying/discriminating the different mitochondrial groups (haplogroups A and B).

Urban public squares as potential hotspots of dog-human contact: A spatial analysis of zoonotic parasites detection in Gran Santiago, Chile

Zoonotic parasites are a major public health problem globally, representing a hazard to human health. The infections occur through contact with different parasite forms. Public squares are a common meeting place for people and dogs, becoming a risk area for transmission to other dogs and humans. A spatial analysis of zoonotic parasite distribution in urban public squares in Gran Santiago, Chile was performed to elucidate its importance, exploring spatial aggregation on positivity rates at commune level. A total of 170 stool samples were analysed; 54 (31.7%) were positive for gastrointestinal-zoonotic parasites. Positivity was detected in 27 (79.4%) squares. Diversity of parasite species was variable across sites. Toxocara canis was the most frequently detected (27 samples, 21/34 squares), followed by Toxascaris leonina (13 samples, 10/34 squares), cestode eggs (10 samples, 9/34 squares), Giardia sp. (6 samples, 5/34 squares), Ancylostomatidae-like eggs (4 samples, 4/34 squares), Cryptosporidium spp. (2 samples, 2/34 squares) and Entamoeba spp. (1 sample, 1/34 square). Spatial autocorrelation (SA) was observed at commune level. The local indicators of the spatial association test showed statistical significance for cestode eggs (p < 0.001) with a negative SA (Moran's I Index = -0.2929, CI-95% = -0.3869--0.1989) and Ancylostomatidae (p = 0.046) with a positive SA (Moran's I Index = 0.1404, CI-95% = 0.0499-0.2309). Toxocara canis is the most prevalent geo-helminth in public places of Santiago, Chile. Spatial autocorrelation was detected for cestode eggs and Ancylostomatidae. Diagnosis and detection of parasites is key for the establishment of control/eradication of environmental dissemination following One Health guidelines.