Canine brucellosis caused by Brucella canis is a neglected zoonosis worldwide and is a leading cause of reproductive failure in dogs, often causing substantial economic losses in breeding kennels. This study aimed to investigate the occurrence of B. canis infection in dogs of commercial breeding kennels located in São Paulo State, Brazil. A total of 753 dogs (183 males and 570 females) from 38 commercial kennels were clinically examined, and blood samples were collected for brucellosis diagnosis through blood culture. The association between clinical manifestations suggestive of brucellosis and positive results through blood culture was determined. Of the 753 dogs tested, 166 (22.0%) had at least one clinical sign suggestive of brucellosis and 158 (20.9%) had positive blood cultures. Seventy-two dogs had positive blood culture and had at least one clinical sign suggestive of brucellosis, while 91 dogs showed at least one clinical manifestation suggestive of brucellosis although blood culture was negative. Of the 38 kennels, 16 (42.1%) had at least one positive dog. The prevalence of infection in each kennel varied from 3.8% to 62.6%. Abortion/stillbirth, failure to conceive and enlargement of lymph nodes were significantly associated with brucellosis in female. No association of clinical signs and positive results in blood culture was observed in males. None of the kennels has been carrying out programmes to control brucellosis, and the sale of infected dogs was considered a common practice yielding risks to the public health, in view of the zoonotic potential of the infection.

This study evaluated the performance of an immunochromatographic test (ICT) for the diagnosis of canine brucellosis caused by Brucella canis, comparing its results with that of the rapid slide agglutination test with and without the use of 2-mercaptoethanol and the agar gel immunodiffusion test (AGID). The microbiological culture, PCR and clinical examination were used as reference. According to the results obtained in clinical examination, blood culture, culture of semen and vaginal swab and PCR in blood, semen and vaginal swab, a total of 102 dogs were divided into three groups: B. canis-infected dogs (Group 1), B. canis-non-infected dogs (Group 2) and dogs with suspected brucellosis (Group 3). The diagnostic sensitivity of RSAT, 2ME-RSAT, AGID and ICT in Group 1 was, respectively, 75%, 37.5%, 27.8% and 89.58%. The diagnostic specificity of RSAT, 2ME-RSAT, AGID and ICT in Group 2 was, respectively, 91%, 100%, 100%, and 100%. In dogs with suspected brucellosis, 9.67% were RSAT positive, none was positive by 2ME-RSAT, 3.22% were AGID positive and 6.45% were ICT positive. The main drawback concerning canine brucellosis diagnosis is the lack of a highly sensitive serological assay to be used as a screening test to the rapid identification of infected animals. The ICT showed a high diagnostic specificity and a diagnostic sensitivity value greater than that observed in the RSAT, 2ME-RSAT and AGID. However, 10.41% of infected dogs had negative results by ICT. These dogs were positive by microbiological culture and/or PCR, indicating active infection and consequently a higher potential of spreading Brucella. Although rapid and simple to perform, the ICT lacked sensitivity to be used as a screening test.

This study presents the pathological, immunohistochemical, and molecular findings associated with the extra-intestinal detection of canine kobuvirus (CaKV) in a 5-month-old Chihuahua puppy, that had a clinical history of bloody-tinged feces. Principal pathological findings were interstitial pneumonia, necrotizing bronchitis, and parvovirus-induced enteritis. Molecular diagnostic methods identified CaKV within the cerebellum, cerebrum, lung, tonsil, and liver. CaKV and rotavirus were not identified within the feces and intestine. Immunohistochemistry (IHC) assays detected antigens of CDV and CAdV-1 in the lungs. These results confirmed the extra-intestinal detection of CaKV in this puppy and represent the first extra-intestinal detection of CaKV in a dog.

Senecavirus A (SVA) has been associated with vesicular disease in weaned and adult pigs and with high mortality of newborn piglets. This study aimed to establish a nested-PCR assay for the routine diagnosis of SVA infection. Tissue samples (n = 177) were collected from 37 piglets of 18 pig farms located in four different Brazilian states. For the nested-PCR, a primer set was defined to amplify an internal VP1 fragment of 316 bp of SVA genome. Of the 37 piglets, 15 (40.5%) and 23 (62.2%) were positive for the SVA in the RT-PCR and nested-PCR assays, respectively. The SVA RNA was detected in 61/177 (34.5%) samples with the RT-PCR, while the nested-PCR assay showed 84/177 (47.5%) samples with the virus (p < 0.05). According to the herds, 11 (61.1%) and 16 (88.9%) of the 18 pig herds were positive for the SVA in the RT-PCR and nested-PCR assays, respectively. Nucleotide sequencing analysis revealed similarities of 98.7-100% among SVA Brazilian strains and of 86.6-98% with SVA strains from other countries. The nested-PCR assay in this study was suitable to recover the SVA RNA in biological specimens, piglets, and/or herds that were considered as negative in the RT-PCR assay, and is proposed for the routine investigation of the SVA infection in piglets, especially when other techniques are not available or when a great number of samples has to be examined.

No abstract

No abstract

DINIZ, J. A. Development, standardization and validation of a real time polymerase chain reaction for the diagnosis of canine. [Desenvolvimento, padronização e validação de reação em cadeia pela polimerase (PCR) em tempo real para diagnóstico da brucelose canina.]. 2018. 84 f. Dissertação (Mestrado em Ciências)

A Brucella canis é uma bactéria intracelular facultativa responsável pela brucelose nos cães, uma doença infectocontagiosa de caráter crônico e zoonótico, endêmica no Brasil e associada a problemas reprodutivos e comprometimento dos sistemas linfoide e articular. A infecção é comumente descrita em canis de reprodutores, sendo de difícil tratamento e controle. Este trabalho relata um surto de brucelose em um canil comercial localizado em Guarulhos (São Paulo), composto por 32 cães (4 machos e 28 fêmeas) de 5 raças distintas, no qual episódios de abortamento foram relatados desde outubro de 2015. A suspeita de brucelose foi aventada apenas um ano e meio após a ocorrência do primeiro episódio de abortamento, sendo realizados anamnese, exames clínicos e diagnósticos sorológico e bacteriológico em todos os cães do plantel. Dos 32 cães, 28 apresentaram pelo menos um sinal clínico compatível com brucelose, sendo o aumento de linfonodos e o abortamento os sinais mais frequentemente observados. Vinte e seis animais apresentaram resultado positivo em pelo menos um dos testes laboratoriais usados para o diagnóstico, indicando prevalência de 81,25% na criação. No diagnóstico microbiológico, houve isolamento de B. canis em amostras de sangue de 22 cães, em amostras de swab vaginal de 9 fêmeas e em sêmen ou swab prepucial de 2 machos. Vinte e três cães apresentaram resultados positivos no sorodiagnóstico. Quando introduzida em criações caninas confinadas, a infecção pode se disseminar rapidamente, levando a grandes perdas reprodutivas. A elevada prevalência observada no canil pode ser relacionada à demora para a investigação da infecção após a ocorrência do primeiro episódio de abortamento, bem como à existência de condições de manejo favoráveis à introdução e rápida disseminação da infecção. Assim, o presente relato alerta para a importância da imediata investigação de problemas reprodutivos em cães por meio de testes laboratoriais para diagnóstico da brucelose canina.