Parasites may exit immunocompromised northern pig-tailed macaques (Macaca leonina) infected with SIVmac239

Parasites can increase infection rates and pathogenicity in immunocompromised human immunodeficiency virus (HIV) patients. However, in vitro studies and epidemiological investigations also suggest that parasites might escape immunocompromised hosts during HIV infection. Due to the lack of direct evidence from animal experiments, the effects of parasitic infections on immunocompromised hosts remain unclear. Here, we detected 14 different parasites in six northern pig-tailed macaques (NPMs) before or at the 50th week of simian immunodeficiency virus (SIV) infection by ELISA. The NPMs all carried parasites before viral injection. At the 50th week after viral injection, the individuals with negative results in parasitic detection (i.e., 08247 and 08287) were characterized as the Parasites Exit (PE) group, with the other individuals (i.e., 09203, 09211, 10205, and 10225) characterized as the Parasites Remain (PR) group. Compared with the PR group, the NPMs in the PE group showed higher viral loads, lower CD4+ T cells counts, and lower CD4/CD8 rates. Additionally, the PE group had higher immune activation and immune exhaustion of both CD4+ and CD8+ T cells. Pathological observation showed greater injury to the liver, cecum, colon, spleen, and mesenteric lymph nodes in the PE group. This study showed more seriously compromised immunity in the PE group, strongly indicating that parasites might exit an immunocompromised host.

A survey of microparasites present in adult migrating Chinook salmon (Oncorhynchus tshawytscha) in south-western British Columbia determined by high-throughput quantitative polymerase chain reaction

Microparasites play an important role in the demography, ecology and evolution of Pacific salmonids. As salmon stocks continue to decline and the impacts of global climate change on fish populations become apparent, a greater understanding of microparasites in wild salmon populations is warranted. We used high-throughput, quantitative PCR (HT-qRT-PCR) to rapidly screen 82 adult Chinook salmon from five geographically or genetically distinct groups (mostly returning to tributaries of the Fraser River) for 45 microparasite taxa. We detected 20 microparasite species, four of which have not previously been documented in Chinook salmon, and four of which have not been previously detected in any salmonids in the Fraser River. Comparisons of microparasite load to blood plasma variables revealed some positive associations between Flavobacterium psychrophilum, Cryptobia salmositica and Ceratonova shasta and physiological indices suggestive of morbidity. We include a comparison of our findings for each microparasite taxa with previous knowledge of its distribution in British Columbia.

Dog overpopulation and burden of exposure to canine distemper virus and other pathogens on Santa Cruz Island, Galapagos

Dog overpopulation and diseases are hazards to native island species and humans on the Galapagos. Vaccination and importation of dogs are prohibited on the Galapagos. Risk management of these hazards requires the use of science-based risk assessment and risk communication. The objectives of the study reported here were (i) to estimate the human:dog ratio and (ii) the prevalence of and identify exposure factors associated with positive antibody titers to canine distemper virus (CDV) and other pathogens, as well as infection with intestinal parasites in owned dogs on Santa Cruz Island, Galapagos in September 2014. The observed human:dog ratio was 6.148:1 which extrapolates to 2503 dogs (two times more than a recent dog count conducted by Galapagos Biosecurity Agency in March 2014). The proportion of spayed female dogs (50%) was higher, compared to neutered male dogs (30%) (p=0.04). Prevalence of dogs with positive antibody titers to CDV was 36% (95% CI=26, 46%), to canine parvovirus was 89% (95% CI=82, 95%), and to canine adenovirus was 40% (95% CI=30, 51%). The frequency of seropositive dogs to CDV was lower in urban dogs (26%), compared to rural dogs (53%) (p<0.05). A positive interaction effect between rural residence and spay/neuter status on seropositivity to CDV was observed, which we discuss in this report. Because vaccination is prohibited, the dog population on Santa Cruz is susceptible to an outbreak of CDV (particularly among urban dogs) with potential spill over to marine mammals. Dog's age (1-2 or 3-14 years old, compared to younger dogs), and residence (rural, urban) were associated with positive antibody titers to parvovirus, adenovirus, Ehrlichia spp., or Anaplasma spp., as well as infection with Ancylostoma spp., an intestinal parasite in dogs that can be transmitted to humans, particularly children. These results provide the most comprehensive assessment of dog overpopulation and exposure to CDV and other pathogens on the Galapagos to date.