VN May 2017

Regulars I From the Journal of the SAVA

From the Journal of the SAVA Enhanced diagnosis of rabies and molecular evidence for the transboundary spread of the disease in Mozambique

Validity of somatic cell count as indicator of pathogen-specific intramammary infections Inge-Marié Petzer, Joanne Karzis, Edward F. Donkin, Edward C. Webb, Eric M.C. Etter Journal of the South African Veterinary Association; Vol 88 (2017), 10 pages. doi: 10.4102/jsava.v88i0.1465 Abstract The objective of this study was to determine whether somatic cell count (SCC) was an effective test, with a sensitivity exceeding 85%, to determine species- specific bacterial infections. In addition, the relation between the SCC and various udder pathogen groups was investigated. SCC thresholds of greater than 200 000 cells/mL were used in quarter and greater than 150 000 cells/mL in composite milk samples. A retrospective study was conducted on a data set for 89 635 quarter and 345 467 composite cow milk samples. Eleven SCC threshold values were used to evaluate the diagnostic efficacy for the following bac­ teria: Gram-positive major pathogens: Staphylococcus aureus, Streptococcus agalactiae, Streptococcus dysgalactiae and Streptococcus uberis ; Gram- negative major pathogens: Escherichia coli, Klebsiella pneumonia and Serratia spp.; minor pathogens: coagulase-negative staphylococci, Micrococcus spp., Staphylococcus pseudintermedius, Streptococcus pyogenes, Enterococcus faecalis, Enterococcus canis, Trueperella pyogenes and other Enterobacteriaceae. Sensitivity and specificity were calculated taking the effect of clustering into account with quarter milk samples. Most samples yielding major Gram-positive pathogens (88.9% in quarter and 79.9% in composite samples) and minor pathogens (61.4% in quarter and 51.7% in composite samples) had SCC greater than 200 000 cells/mL. Sensitivity of the SCC test to detect major pathogens at an SCC threshold of greater than 200 000 cells/mL in quarter samples and greater than 150 000 cells/mL in composite milk samples was 88.2% and 84.2%, respectively, but specificity was low (57.7% and 52.8%, respectively). v

Andre Coetzer, Iolanda Anahory, Paula T. Dias, Claude T. Sabeta, Terence P. Scott, Wanda Markotter, Louis H. Nel

Journal of the South African Veterinary Association; Vol 88 (2017), 9 pages. doi: 10.4102/jsava.v88i0.1397 Abstract Rabies is a neglected zoonotic disease with veterinary and public health significance, particularly in Africa and Asia. The current knowledge of the epidemiology of rabies in Mozambique is limited because of inadequate sample sub­ mission, constrained diagnostic capabilities and a lack of molecular epidemiological research. We wanted to con- sider the direct, rapid immunohistochemical test (DRIT) as an alternative to the direct fluorescent antibody (DFA) for rabies diagnosis at the diagnostic laboratory of the Central Veterinary Laboratory (CVL), Directorate of Animal Science, Maputo, Mozambique. Towards this aim, as a training exercise at the World Organisation for Animal Health (OIE) Rabies Reference Laboratory in South Africa, we performed the DRIT on 29 rabies samples from across Mozambique. With the use of the DRIT, we found 15 of the 29 samples (52%) to be negative. The DRIT-negative samples were retested by DFA at the OIE Rabies Reference Laboratory, as well as with an established real-time Polymerase chain reaction, confirming the DRIT-negative results. The DRIT-positive results (14/29) were retested with the DFA and subsequently amplified, sequenced and subjected to phylogenetic analyses, confirming the presence of rabies RNA. Molecular epidemiological analyses that included viruses from neighbouring countries suggested that rabies cycles within Mozambique might be implicated in multiple instances of cross-border transmission. In this regard, our study has provided new insights that should be helpful in informing the next steps required to better diagnose, control and hopefully eliminate rabies in Mozambique. v

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18 Mei/May 2017