Detection of agents associated with respiratory diseases of swine by real time PCR

Health profile of free-range wild boar (Sus scrofa) subpopulations hunted in Santa Catarina State, Brazil

Wild boars represent a potential dissemination source of important pathogens to public and animal health, since they can host several pathogens. This study aimed to evaluate the health profile of wild boars hunted for population control in the state of Santa Catarina (SC), south of Brazil. For this study, tissue and blood samples were collected from 61 wild boars hunted from October 2017 to November 2018. All 61 serum samples were screened for antibodies by different assays, presenting the following seroprevalence: 52.4% for porcine circovirus type 2 (PCV2); 21.3% for Leptospira spp.; 19.7% for Mycoplasma hyopneumoniae; 13.1% for hepatitis E virus (HEV); and 9.8% for influenza A virus (IAV). No seroreaction was observed for Brucella spp. and classical swine fever virus (CSFV). At necropsy, the main lesions observed were evidence of pulmonary metastrongylid parasites, haemorrhagic lymph nodes and white-spotted liver. Histopathological analyses mainly showed interstitial pneumonia, bronchopneumonia and bronchi-associated lymphoid tissue (BALT) hyperplasia. There was a significant association between metastrongylid parasitism and BALT hyperplasia in lungs. Pathological findings of wild boars indicate that the assessed individuals were not exposed to notifiable diseases, such as CSFV, African swine fever virus and foot-and-mouth disease, which cause economic damage by non-tariff trade barriers. However, the detection of antibodies against PCV2 and M. hyopneumoniae, pathogens that impact commercial production, indicates the circulation of these agents, with frequency variation in wild populations. This shows the potential risk of pathogen transmission among domestic swine populations and free-living ones. The detection of antibodies against zoonotic agents such as HEV, IAV and Leptospira spp., other than characterizing the pathogens' circulation in these populations, suggests a potential risk to public health and pig farming, depending on the interactions established with the environment, humans and domestic swine.

Isolation and identification of Streptococcus suis from sick pigs in Bali, Indonesia

Objective

Streptococcus suis (S. suis) is a causative agent for various syndromes in pigs. It can be transmitted to humans with typical symptoms of meningitis and death. Although human infections have been confirmed at Bali Referral Hospital, Indonesia, since 2014, the bacteria have not been isolated from pigs. Here, we provide confirmation of the presence of the bacteria in sick pigs in the province.

Results

Streptococcus suis was confirmed in 8 of 30 cases. The final confirmation was made using PCR and sequencing of the glutamate dehydrogenase (GDH) and recombination/repair protein (recN) gene fragments. Upon PCR serotyping, two were confirmed to be serotype 2 or 1/2. Prominent histopathological lesions of confirmed cases were meningitis, endocarditis, pericarditis, bronchopneumonia, enteritis and glomerulonephritis. The dominant inflammatory cells were neutrophils and macrophages. Further research is needed to understand the risk factors for human infection. Community awareness on the risk of contracting S. suis and vaccine development are needed to prevent human infections.