Mixed mycotic rhinitis and pneumonia in wild boars
Zlotowski, PriscilaAlmeida, Paula Rodrigues deBoos, Gisele SilvaSanches, Edna Maria CavalliniFerreiro, LaerteSpanamberg, AndréiaRavazzolo, Ana PaulaDriemeier, David
Background: Wild boar population is present worldwide. Contact between wild boars and domestic pigs may occur occasionally, and several diseases, as well as the occurrence of opportunistic infections are observed in both species. Mycotic rhinitis and pneumonia were reported before in pig herds, mainly associated with immunosuppression caused by viral infection. This study reports the occurrence of mycotic rhinitis in two wild boars due to Aspergillus fumigatus, A. fl avus and Candida albicans, together with Pneumocystis sp. in the lungs, originating from a herd infected with PCV2. Cases: In a commercial wild boar herd, poor body condition, sneezing and diarrhea were observed. Three animals were euthanized and, in two of them, yellow and green plaque-like masses of fungal growth in the mucosal and in cartilage surface and accentuated atrophy of nasal turbinates were observed. Additionally, multifocal subcutaneous abscesses in the maxillary area and bilateral reddening of the ocular mucosa with muco-purulent discharge were noted. Microscopically, in fragments from the nasal cavity of the two affected wild pigs, massive ulceration of the mucosal surface and presence of hyphae with septations and dichotomous branching and pseudohyphae were observed. Multifocal moderated interstitial pneumonia and alveolar edema were the main histological lesions founded in the lungs of 3 animals. In the lymph nodes multifocal moderated lymphoid depletion and lymphohistiocytic infi ltrated was the main microscopical lesion. Aspergillus fumigatus, A. fl avus and Candida albicans were isolated in nasal cavity. Pseudomonas aeruginosa was isolated from the subcutaneous abscesses and Staphylococcus hyicus and Streptococcus equisimilis from ocular swab. Pneumocystis was detected in lungs from the three wild boars by nested PCR, Grocott´s staining and immunohistochemistry (IHC). Porcine circovirus 2 (PCV2) was detected in lungs by PCR. Virus detection by IHC was only confi rmed in one wild boar. Discussion: Diagnostic of mycotic rhinitis and pneumonia was based on macroscopical and microscopical fi ndings, as well as mycological analysis, IHC and Groccott ´s methenamine staining. Pneumocystis carinii, Aspergillus spp. and Candida spp. are considered as opportunistic fungal pathogens commonly associated with immunosuppression in animals and humans and have been found in lungs and in muco-cutaneous tissue of PMWS affected pigs. Clinically, immunodeficiency is usually associated with illness caused by organisms of low pathogenicity or well-know secondary pathogens, among other factors. Besides immunodefi ciency, prolonged antimicrobial therapy is another predisposing factor to the development of mycotic infections, well described in animals. In the present report, antimicrobial therapy was performed when respiratory signs were noted in therapeutic doses, suggesting that massive antibiotic use was not the trigger of mycotic rhinitis. PCV2 IHC result positive only in one wild pig, although all the samples were positive by PCR. This fi nding could indicate a subclinical infection or a recovery phase of the disease in the IHC negative cases, as previously suggested for domestic and wild pigs using in situ hybridization. PCV2 load in wild boar was lower when compared with domestic pigs. A viral load higher than 108 PCV2 genomes per 500 ng DNA was required to give a visible IHC staining in swine. Although quantitative PCR it was not used in order to detect PCV2 in the present report, the viral load could be another possible explanation for the IHC negative cases observed. The role of PCV2 as a cause of immunosupression, facilitating the infection with secondary agents as Aspergillus, Candida and Pneumocystis cannot be ruled out.(AU)
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