Bacterial Pneumonia in Captive Wild Boars in Southern Brazil - Etiological and Pathological Causes

Background: Respiratory diseases are one of the major health issues described in intensive pig production, causing important economic losses. However, there is little information on the prevalence, etiology and clinical-pathological presentation of these diseases in wild boars. For this reason, this work investigated the presence in captive wild boars of pneumonic lesions and bacterial pathogens commonly detected and associated with respiratory diseases in domestic pigs.Materials, Methods & Results: A total of 226 captive wild boar lungs from two farms were examined in a slaughterhouse in Southern Brazil. The pneumonic lesions were classified as cranioventral, dorsocaudal, and disseminated, and the quantification of lesions was calculated. From the total of 226 lungs, 121 were collected for laboratory examination. Lungs with macroscopic lesions suggestive of pneumonia were collected for histological, bacteriological and molecular analysis. The molecular analysis was performed to detect the presence of Actinobacillus (A.) pleuropneumoniae, Glaesserella (G.) parasuis, Mycoplasma (M.) hyopneumoniae, Mycoplasma (M.) hyorhinis and Streptococcus (S.) suis serotype 2. The percentages of histological lesions and bacterial agents and their association were calculated. Cranioventral consolidation (75.2%) was the most prevalent macroscopic lung lesion, followed by disseminated (21.5%) and dorsocaudal (3.3%) distribution. Microscopically, chronic lesions were the most prevalent, representing 70.2% of the lungs. Moreover, BALT hyperplasia was present in 86.5% of the lungs, suppurative bronchopneumonia in 65.7%, and alveoli infiltrate in 46.8%. Six bacterial pathogens commonly described as agents of pig pneumonia were identified by bacterial or molecular methods: Pasteurella (P.) multocida, S. suis, M. hyopneumoniae, A. pleuropneumoniae, G. parasuis and M. hyorhinis. Twenty-eight different combinations of pathogens were identified in 84 samples (69.4%). The most common combinations were: M. hyopneumoniae and A. pleuropneumoniae (13.1%), M. hyopneumoniae, G. parasuis and M. hyorhinis (10.7%), and M. hyopneumoniae, A. pleuropneumoniae and G. parasuis (8.3%). Additionally, M. hyopneumoniae was the most frequent pathogen detected in this study, representing 58.7% of the samples. The detection of M. hyopneumoniae and M. hyorhinis by PCR was associated with the presence of BALT hyperplasia (P < 0.05) and there was also an association between the detection of M. hyopneumoniae by PCR and suppurative bronchopneumonia (P < 0.05). In addition, a significant association (P < 0.05) between the detection of M. hyopneumoniae and A. pleuropneumoniae by PCR and the histological classification (acute, subacute or chronic lesions) was observed.Discussion: The results of this study were similar to those observed in slaughtered domestic pigs, although, the detection of opportunist pathogens was less frequent than that usually described in pig pneumonia. The high prevalence of pneumonia in captive wild boars at slaughter and the similar characteristics of pneumonia in captive wild boars and domestic pigs suggest that the close phylogenetic relationship between pigs and wild boars could influence the susceptibility of both species to the colonization of the same pathogens, indicating that captive wild boars raised in confined conditions could be predisposed to respiratory diseases, similar to domestic pigs. Keywords: Mycoplasma hyopneumoniae, lung consolidation, slaughter, Sus scrofa, swine.

Occurrence of gastrointestinal parasitic diseases of swine in different production phases in commercial pig farms from the State of Santa Catarina, southern Brazil

ABSTRACT Gastrointestinal parasites are important, since they can cause a decrese in the performance of swine. The occurrence of parasites in pig farms can create economic losses such as reduction in the value of carcasses and increasing expenses with medicines and veterinary assistance. This study aimed at investigating the occurrence of intestinal parasites in different phases of production reared pigs in intensive prodution systems in the western region of the State of Santa Catarina. A total of 403 fecal samples were analyzed, of which 51.86% were positive for one or more parasites in different phases of production. Finishing pigs had the highest prevalence of parasites (60.19%) followed by nursery pigs (55.44%), pigs in breading sows (50.49%), and suckling piglets (40.81%). Strongylida parasites had higher occurrence (28.78%), and were also the most frequent in the finishing, breading sows, and nursery phases. Coccidia were more occurrent in suckling piglets. This study highlights the need of implementing suitable antiparasitic control measures in all phases of swine production associated with a surveillance system for the diagnosis of endoparasite infection in pigs. Our results demonstrate that endoparasites are highly occurring in pigs, even in intensive system animals on technified farms.

Unravelling the genetic components involved in the immune response of pigs vaccinated against influenza virus

A genome-wide association study for immune response to influenza vaccination in a crossbred swine population was conducted. Swine influenza is caused by influenza A virus (FLUAV) which is considered one of the most prevalent respiratory pathogens in swine worldwide. The main strategy used to control influenza in swine herds is through vaccination. However, the currently circulating FLUAV subtypes in swine are genetically and antigenically diverse and their interaction with the host genetics poses a challenge for the production of efficacious and cross-protective vaccines. In this study, 103 pigs vaccinated with an inactivated H1N1 pandemic virus were genotyped with the Illumina PorcineSNP60V2 BeadChip for the identification of genetic markers associated with immune response efficacy to influenza A virus vaccination. Immune response was measured based on the presence or absence of HA (hemagglutinin) and NP (nucleoprotein) antibodies induced by vaccination and detected in swine sera by the hemagglutination inhibition (HI) and ELISA assays, respectively. The ELISA test was also used as a measurement of antibody levels produced following the FLUAV vaccination. Associations were tested with x(2) test for a case and control data and using maximum likelihood method for the quantitative data, where a moderate association was considered if p<5×10(-5). When testing the association using the HI results, three markers with unknown location and three located on chromosomes SSCX, SSC14 and SSC18 were identified as associated with the immune response. Using the response to vaccination measured by ELISA as a qualitative and quantitative phenotype, four genomic regions were associated with immune response: one on SSC12 and three on chromosomes SSC1, SSC7, and SSC15, respectively. Those regions harbor important functional candidate genes possibly involved with the degree of immune response to vaccination. These results show an important role of host genetics in the immune response to influenza vaccination. Genetic selection for pigs with better response to FLUAV vaccination might be an alternative to reduce the impact of influenza virus infection in the swine industry. However, these results should to be validated in additional populations before its use.

Burn-associated bone disease in sheep: roles of immobilization and endogenous corticosteroids

To determine the role of immobilization in the pathogenesis of burn-associated bone disease, we selected the sheep as a model to study the effects of burn injury compared with a sham-burned control group. Seven of the sheep were subjected to controlled 40% flame burn, and seven underwent anesthesia with arterial and venous cannulation but without burn. After labeling newly formed bone with tetracycline and calcein, the sheep were killed 2 weeks after burn or sham burn, and the iliac crest and lumbar vertebrae were analyzed for histomorphometry. Analysis failed to demonstrate a significant reduction of bone formation rate in the burned sheep. Osteoid area and surface and osteoblast surface, which correlated significantly with bone formation rate (r = 0.49, p < 0.025), were reduced in the burned sheep. Results suggest that immobilization may play a primary role in the pathogenesis of burn-associated bone disease, but the presence of differences in other histomorphometric features indicates the bone disease is multifactorial.

Elimination of PBBs in rats. Effect of mineral oil and/or feed restriction

Rats were fed polybrominated biphenyls (PBBs) at 0.1 to 100.0 ppm for 14 d and then treated to hasten the removal of PBBs with 0, 5, or 10% mineral oil (MO) and/or 0, 15, 30, or 45% feed restriction (FR) for 21 d. PBB body burdens were determined at d 14 and expressed on a log-log basis by Y = 0.91X + 2.179 (r2 = 0.974), where X = log of PBB concentration in diet (ppm) and Y = log of PBB body burden (micrograms). After 21 d withdrawal, body burdens were expressed by the equation Y = 0.787X + 2.218 (r2 = 0.95). The most effective withdrawal treatment was 10% MO + 45% FR producing a reduction of body burdens inversely related to prior body burdens (69% at 0.1 ppm to 23% at 100 ppm). Body weights and fat content were significantly (p less than or equal to .05) reduced by feed restriction, with fat content only 39% of controls at 21 d off. Mortality averaged 0, 13.6, and 35.8% for rats fed 0, 5, or 10% MO, and 25, 15, 8.6, and 3.7% for rats feed restricted at 0, 15, 30, and 45%, respectively. Histopathology of the dead and moribund rats indicated that the clinical signs were not characteristic of PBB toxicity. In a second experiment, safflower oil at 3.5% or excess vitamins prevented the mortality and clinical signs associated with MO during withdrawal from 100 ppm PBBs. Based on these data and those in the literature, PBBs interfere with vitamin utilization.