Astroviruses cause disease in a variety of species. Yet, little is known about the epidemiology of a majority of astroviruses including porcine astrovirus type 3 (PoAstV3), which is a putative cause of polioencephalomyelitis in swine. Accordingly, a cross-sectional study was conducted on sow farms with or without reported PoAstV3-associated neurologic disease in growing pigs weaned from those farms. Additionally, a conveniently selected subset of piglets from one farm was selected for gross and histologic evaluation. The distribution of PoAstV3 in the enteric system was evaluated through in situ hybridization. PoAstV3, as detected by RT-qPCR on fecal samples, was frequently detected across sows and piglets (66–90%) on all farms (65–85%). PoAstV3 was detected subsequently at a similar detection frequency (77% vs 85%) on one farm after three months. Viral shedding, as determined by the cycle quantification value, suggests that piglets shed higher quantities of virus than adult swine. No link between gastrointestinal disease and PoAstV3 was found. However, PoAstV3 was detected by in situ in myenteric plexus neurons of piglets elucidating a possible route of spread of the virus from the gastrointestinal tract to the central nervous system. These data suggest PoAstV3 has endemic potential, is shed in the feces at greater quantities by suckling piglets when compared to sows, and infection is widespread on farms in which it is detected.

Very little information is available regarding the demographics of the demodicosis in canines of Kathmandu valley and in Nepal as a whole. In this study, we determined the prevalence of the demodicosis and its associated risk factors from 110 canines of Kathmandu valley including both sheltered and free-roaming. The skin scrapping collected was dissolved in 10% KOH for the microscopic diagnosis of the mites. The overall prevalence of demodectic mange was found to be 29.1%. There was significant difference (p<0.05) between the prevalence rate among puppy (49.0%), adult (6.9%) and senior (33.33%). Whereas, there was no significant difference (p>0.05) between the prevalence rate among female (22.9%) and male (36.7%). Similarly, there was no significant difference (p>0.05) between the prevalence rate among short hair (40.7%), medium (25.67%) and long hair (28.5%). The association between the prevalence rate among good health status (10.7%) and poor health status (55.5%) is significant (p<0.05). Similarly, there was significant difference (p<0.05) between the prevalence rate among the free-roaming (48.9%) and the owned dogs (13.1%). At last, there was no significant association (p>0.05) between the prevalence rate among the pure breed (27.7%), cross (25.9%) and mongrel (37.5%). This study shows that demodectic mange is somewhat serious skin infection in canines of Kathmandu valley. The high significant association of age, health status and management with its prevalence suggests that the disease is more common in dogs which are left uncared and whose immune system is disturbed. Whereas, sex, breed and type of the hair of the dog did not have such significant relation with its prevalence.  As demodicosis is a huge problem in street dogs, concerned organizations and authorities should develop proper planning for street dog management and their health care. Int J Appl Sci Biotechnol, Vol 3(3): 459-463

Astroviruses (AstVs) cause disease in a wide variety of species. Porcine AstVs are highly genetically diverse and conventionally assigned to five genetic lineages (PoAstV1-5). Due to the increasing evidence that porcine astrovirus type 3 (PoAstV3) is a cause of encephalomyelitis in swine and to elucidate important ecologic characteristics, the infection dynamics and environmental distribution of PoAstV3 were investigated in a herd with PoAstV3-associated neurologic disease. Over a 22 week period, the frequency of PoAstV3 fecal shedding varied by pig and age. The peak detection by RT-qPCR of PoAstV3 on fecal swabs (95%; 61 of 64) occurred at 3 weeks of age. The lowest frequency of detection was at 21 weeks of age (4%; 2 of 47); however, the frequency increased to 41% (19 of 46) at the final sampling time point (25 weeks of age). Viremia was rare (0.9%: 4 of 433). Detection in oral fluid was consistent with 75% to 100% of samples positive at each time point. Pens and feeders also had a high rate of detection with a majority of samples positive at a majority of sampling time points. Based on the data presented, PoAstV3 can be consistently detected in the environment with a majority of pigs being infected and a subset intermittently shedding the virus in feces out to 25 weeks of age. These findings suggest the importance of as-yet unidentified risk factors associated with the development of PoAstV3-associated polioencephalomyelitis.

A PEDV/PDCoV/TGEV/SADS-CoV/XIPC 5-plex real-time RT-PCR was developed and validated for the simultaneous detection and differentiation of four swine enteric coronaviruses (PEDV, PDCoV, TGEV and SADS-CoV) in one PCR reaction (XIPC serves as an exogenous internal positive control). The 5-plex PCR had excellent analytical specificity, analytical sensitivity, and repeatability based on the testing of various viral and bacterial pathogens, serial dilutions of virus isolates, and in vitro transcribed RNAs. The 5-plex PCR had comparable diagnostic performance to a commercial PEDV/TGEV/PDCoV reference PCR, based on the testing of 219 clinical samples. Subsequently, 1807 clinical samples collected from various U.S. states during 2019–2021 were tested by the 5-plex PCR to investigate the presence of SADS-CoV in U.S. swine and the frequency of detecting swine enteric CoVs. All 1807 samples tested negative for SADS-CoV. Among the samples positive for swine enteric CoVs, there was a low frequency of detecting TGEV, an intermediate frequency of detecting PDCoV, and a high frequency of detecting PEDV. Although there is no evidence of SADS-CoV presence in the U.S. at present, the availability of the 5-plex PCR will enable us to conduct ongoing surveillance to detect and differentiate these viruses in swine samples and other host species samples as some of these coronaviruses can cause cross-species infection.

Porcine astroviruses (PoAstVs) have been reported globally and are divided into at least five distinct lineages (PoAstV1‐PoAsV5). The primary objective of this review was to summarize the scientific literature about the frequency of detection, associated clinical presentations and type of samples and diagnostic tools used for the detection of porcine astroviruses. The secondary objective was to summarize the body of knowledge about the causal role in disease of PoAstVs using the Bradford Hill framework. A search was conducted using Centre for Biosciences and Agriculture International (CABI), MEDLINE, American Association of Swine Veterinarians (AASV) Swine Information Library (SIL) abstracts, swine conferences including American College of Veterinary Pathologists (ACVP) and American Association of Veterinary Laboratory Diagnosticians (AAVLD). From 168 studies identified by the search, 29 studies were eligible. Results indicated that 69% (20/29) of the literature on PoAstVs have been published between 2011 and 2018. Of 29 papers, 52% were detection studies (15 of 29) and 48% (14 of 29) were case–control studies. Seventy‐two per cent (21 of 29) reported differential diagnosis and 10% (3 of 29) reported histologic lesions, out of which 67% (2 of 3) associated the detection of PoAstV3 with development of polioencephalomyelitis. PCR‐based assays were the most common diagnostic tools.