Influenza A virus infection in pigs from Mozambique

Swine  influenza  (SI)  is  an  acute  and  highly  contagious  disease  of  the  respiratory tract of pigs caused by swine influenza A virus (SIA). The disease causes economic losses in swine production and is of great public importance for its zoonotic potential. The aims of the present  study  were  to  report SIA infection  in  pigs  from  Mozambique  and  characterize  the anatomopathological  and  immunohistochemical  features  of  associated  lung  lesions.  Lungs from  457  slaughtered  pigs  were  subjected  to  gross  evaluation  and 38  (8.3%)  lungs  with cranioventral  consolidation  were  collected  from  a slaughterhouse  in  Matola  City,  Southern Mozambique. Consolidation areas in each lung lobe  were classified in 4 grades according to the lesion extension. Samples with consolidated lung tissue were examined for histopathology and  immunohistochemistry  for  the  presence  of  SIA,  Porcine  circovirus  type  2  (PCV2)  and Mycoplasma  hyopneumoniae  antigens.  The  lungs  had  multifocal  to  coalescing  areas  of consolidation observed most frequently in the craniallobes. The lesions involved mainly one or three  pulmonary  lobes  and  grade  1  and  2  lesions  were  the  most  frequent.  The  main histopathological  findings  were  necrotizing  bronchiolitis  (23/38),  alveolar  neutrophil infiltration (24/38), type II pneumocytes hyperplasia (26/38), peribronchiolar lymphoid tissue hyperplasia  (28/38)  and  interstitial  mononuclear  cells  infiltrate  (29/38). SIA  antigen  was detected by immunohistochemistryin 84.3% (32/38) of lung samples and all lung samples were negative  for  PCV2  and Mycoplasma  hyopneumoniaantigense. Pigs  that  presented  a  positive result on IHQ were from Matutuine district (5/32), Moamba district (2/32), Namaacha district (21/32), Boane district (3/32) and Matola city (1/32). These results demonstrate that SIA is a cause of pneumonia in pigs in Mozambique

Characterization of tuberculous lesions in naturally infected African buffalo (Syncerus caffer)

Thesis (MScMedSc (Biomedical Sciences. Medical Biochemistry))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: Mycobacterium bovis has a wide host range and infects many wild and domestic animal species as well as humans. African buffalo (Syncerus caffer) is considered to be a wildlife reservoir of M. bovis in certain environments in South Africa, such as in the Kruger National Park (KNP) and Hluhluwe-iMfolozi Park (HiP). A detailed pathological study was conducted on 19 African buffalos (Syncerus caffer) from a herd in the HiP in South Africa. The animals tested positive to the intradermal bovine tuberculin test and were euthanazed during a test-and-cull operation to decrease the prevalence of bovine tuberculosis (bTB) in the park. The superficial, head, thoraxic and abdominal lymph nodes and the lungs were examined grossly for presence of tuberculous lesions and were scored on a 1-5 scale for macroscopic changes. The gross lesions were examined histologically and scored I-IV according to a grading system used for bTB lesions in domestic cattle. Macroscopical lesions were limited to the retropharyngeal, bronchial, and mediastinal lymph nodes and the lungs. The most frequently affected lymph nodes were the bronchial (16/19) and mediastinal (11/19). All four grades of microscopic lesions were observed, although grade II lesions were the most frequent. Acid-fast bacilli were observed only rarely. Bovine tuberculosis was confirmed by PCR analyses. All animals were in good body condition and most of the lesions were in an early stage of development, indicating an early stage of the disease. The absence of lesions in the mesenteric lymph nodes and the high frequency of lesions in respiratory tract associated lymph nodes suggest that the main route of M. bovis infection in African buffalo is inhalatory rather than alimentary. This study presents a systematic evaluation and semiquantification of the severity and stages of development of tuberculous lesions in buffalo. The results may contribute to i) the understanding of the pathogenesis of the disease, ii) the evaluation of experimental models of M. bovis infection in Syncerus caffer, and iii) the interpretation of pathological data from vaccination trials.AFRIKAANSE OPSOMMING: Mycobacterium bovis het ‘n wye reeks van gashere en dit infekteer verskeie wilde en mak dierespesies, sowel as mense. Die buffel (Syncerus caffer) word beskou as die wild reservoir van M. bovis in sekere dele van Suid Afrika, soos in die Kruger Nasionale Park (KNP) en Hluhluwe-iMfolozi Park (HiP). ‘n Breedvoerige patologiese studie is uitgevoer op 19 buffels afkomstig vanaf ‘n trop in die HiP in Suid Afrika. Die diere het almal positief getoets vir die intradermale beestuberkulin toets en is uitgesit tydens ‘n toets-en-slag operasie met die doel om die voorkoms van beestuberkulose (bTB) in die park te bekamp. Die oppervlakkige, kop, toraks en abdominale limfknope en longe is oorsigtelik ondersoek vir die teenwoordigheid van tuberkulose letsels en was ‘n punt toegeken op ‘n skaal van 1-5 vir die teenwoordigheid van makroskopiese veranderinge. Die opsigtelike letsels is histologies ondersoek en ‘n I-IV punt toegeken volgens die gradering wat gebruik word vir bTB letsels in beeste. Makroskopiese letsels was beperk tot die retrofaringeale, brongiale, en mediastinale limfknope en in die longe. Die brongiale (16/19) en mediastinale (11/19) limfknope was meestal geaffekteerd. Al vier grade van mikroskopiese letsels is gevind, alhoewel graad II letsels die volopste was. Suur-vaste basille is slegs selde waargeneem. Beestuberkulose is bevestig deur PKR analises. Al die diere was in ‘n goeie kondisie en meeste van die letsels was in ‘n vroeë stadium van ontwikkeling, wat aandui op ‘n vroeë fase van die siekte. Die afwesigheid van letsels in die mesenteriese limfknope en die hoë frekwensie van letsels in die lugweg geassosieerde limfkliere dui daarop dat the belangrikste roete van M. bovis infeksie in die buffel deur inaseming geskied eerder as deur opname in die spysverteringskanaal. Hierdie studie bied ‘n stelselmatige evaluering en semi-kwantifisering van die graad van erns en die stadia van ontwikkeling van tuberkulose letsels in buffels. Die resultate kan bydra tot i) die begrip van die patogenese van die siekte, ii) die evaluering van eksperimentele modelle van M. bovis infeksie in Syncerus caffer, en iii) die interpretasie van patologiese data van inentingsproewe