Monthly Archives: December 2020

Porcine reproductive and respiratory syndrome (PRRS) is currently the most detrimental disease in the U.S swine industry. Clinical signs of PRRS virus (PRRSv) infection in breeding herds include reproductive failure with abortions, stillbirths, premature farrowings and increased pre-weaning mortality. Serum from due-to-wean piglets is considered the most suitable specimen to monitor PRRSv infection and stability in breeding herds. However, processing fluids (PF – the serosanguinous exudate resultant of the collection of tails and testicles during processing) are a new specimen proposed to monitor piglets at processing (3-5 days of age) and udder wipes (UW) of lactating sows is yet another specimen to monitor infection status of suckling piglets indirectly. Here, we assessed which specimen type (e.g. sera, testicles, tails or UW) should be used to accurately establish the PRRSv status of a litter. Twenty-four litters were conveniently selected on a farm at 10 weeks post PRRSv outbreak. Blood samples, tails and testicles from every piglet in a litter, and an udder skin wipe from the sow were collected at processing (3-5 days). Individual litter testicles and tails as well as the udder wipe were placed each in a reclosable bag to prevent cross-contamination. Sensitivity (Se), specificity (Sp), negative predictive value (NPV), positive predictive value (PPV) and global agreement at the litter level were calculated using the sera results of the litter as the gold standard. The optimum cycle threshold (Ct) value to classify a sample as negative was ≥35 for serum and ≥36 for the aggregated samples (testicles, tails, and UW) based on the ROC curve analysis. Using those thresholds, the fluid collected from the testicles showed the best overall performance (Se = 92 % [62-100]; Sp = 82 % [48-98], NPV = 90 % [55-100], PPV = 85 % [55-98], global agreement = 87 %) compared to tail fluid and UW. Sensitivity of the tail fluid was 62 % (32-86) and the UW was 23 % (5-54), both of which yielded a 100 % specificity and PPV. This study provides information on the contribution of each of the tissues collected at processing on the detection of PRRSv, which becomes relevant in countries were castration and/or tail docking is banned. Vilalta C, Sanhueza J, Schwartz M, Kikuti M, Torremorell M, Corzo C. Assessing the litter level agreement of RT-PCR results for porcine reproductive and respiratory syndrome virus in testicles, tails and udder wipes diagnostic samples relative to serum from piglets. Prev Vet Med. 2020 Nov. https://doi.org/10.1016/j.prevetmed.2020.105211

The USDA continues to consider and implement regulatory pathways for evolving scenarios, needs, and technologies. The intent of this report is to make veterinarians and other users of veterinary biologics aware of recent regulatory additions and changes, particularly in the area of veterinary vaccines. These include new licensure pathways to increase product availability, standardization of labeling, and increased transparency regarding adverse event reports and the efficacy and safety studies accepted by the USDA for product licensure. This report did not undergo scientific peer review. Erdman M, Clough N, Hauer P. Review of updated regulations and product license categories for veterinary vaccines in the United States. JAVMA. 2020 Dec. https://doi.org/10.2460/javma.2020.257.11.1142

Reston virus (RESTV), an ebolavirus, causes clinical disease in macaques but has yet only been associated with rare asymptomatic infections in humans. Its 2008 emergence in pigs in the Philippines raised concerns about food safety, pathogenicity, and zoonotic potential, questions that are still unanswered. Until today, the virulence of RESTV for pigs has remained elusive, with unclear pathogenicity in naturally infected animals and only one experimental study demonstrating susceptibility and evidence for shedding but no disease. Here we show that combined oropharyngeal and nasal infection of young (3- to 7-wk-old) Yorkshire cross pigs with RESTV resulted in severe respiratory disease, with most animals reaching humane endpoint within a week. RESTV-infected pigs developed severe cyanosis, tachypnea, and acute interstitial pneumonia, with RESTV shedding from oronasal mucosal membranes. Our studies indicate that RESTV should be considered a livestock pathogen with zoonotic potential. Haddock E, Saturday G, Feldmann F, Hanley P, Okumura A, Lovaglio J, Long D, Scott D, Pulliam M, Richt J, de Wit E, Feldmann H. Reston virus causes severe respiratory disease in young domestic pigs. PNAS. 2021 Jan. https://doi.org/10.1073/pnas.2015657118

Toxoplasma gondii infections are common in humans and animals worldwide. Toxoplasma gondii infection in pigs continues to be of public health concern. Pigs are important for the economy of many countries, particularly, USA, China, and European countries. Among the many food animals, pigs are considered the most important for T. gondii transmission in USA and China because viable parasites have rarely been isolated from beef or indoor raised chickens. Besides public health issues, T. gondii causes outbreaks of clinical toxoplasmosis in pigs in China, associated with a unique genotype of T. gondii (ToxoDB genotype #9 or Chinese 1), rarely found in other countries. The safety of ready to eat pork products with respect to T. gondii infection is a matter of recent debate. Here, we review in detail seroprevalence, prevalence of viable and nonviable T. gondii, epidemiology, risk assessment, diagnosis, and curing of pork products containing T. gondii for the past decade. This review will be of interest to biologists, parasitologists, veterinarians, and public health workers. Dubey J, Cerqueira-Cézar C, Murata F, Kwok O, Hill D, Yang Y, Su C. All about Toxoplasma gondii infections in pigs: 2009-2020. Vet Pasisitol. 2020 Dec. https://doi.org/10.1016/j.vetpar.2020.109185