The North American distributional potential of the recently invaded tick, Haemaphysalis longicornis, was estimated using occurrence data from its geographic range in other parts of the world and relevant climatic data sets. Several hundred candidate models were built using a correlative maximum entropy approach, and best-fitting models were selected based on statistical significance, predictive ability, and complexity. The median of the best-fitting models indicates a broad potential distribution for this species, but restricted to three sectors—the southeastern United States, the Pacific Northwest, and central and southern Mexico.

No abstract

Severe fever with thrombocytopenia syndrome virus (SFTSV) is spreading rapidly in Asia. This virus is transmitted by the Asian longhorned tick ( Haemaphysalis longicornis ), which has parthenogenetically and sexually reproducing populations. Parthenogenetic populations were found in ≥15 provinces in China and strongly correlated with the distribution of severe fever with thrombocytopenia syndrome cases. However, distribution of these cases was poorly correlated with the distribution of populations of bisexual ticks. Phylogeographic analysis suggested that the parthenogenetic population spread much faster than bisexual population because colonization is independent of sexual reproduction. A higher proportion of parthenogenetic ticks was collected from migratory birds captured at an SFTSV-endemic area, implicating the contribution to the long-range movement of these ticks in China. The SFTSV susceptibility of parthenogenetic females was similar to that of bisexual females under laboratory conditions. These results suggest that parthenogenetic Asian longhorned ticks, probably transported by migratory birds, play a major role in the rapid spread of SFTSV.

Salmonella enterica serovar Wangata (S. Wangata) is an important cause of endemic salmonellosis in Australia, with human infections occurring from undefined sources. This investigation sought to examine possible environmental and zoonotic sources for human infections with S. Wangata in north-eastern New South Wales (NSW), Australia. The investigation adopted a One Health approach and was comprised of three complimentary components: a case–control study examining human risk factors; environmental and animal sampling; and genomic analysis of human, animal and environmental isolates. Forty-eight human S. Wangata cases were interviewed during a 6-month period from November 2016 to April 2017, together with 55 Salmonella Typhimurium (S. Typhimurium) controls and 130 neighbourhood controls. Indirect contact with bats/flying foxes (S. Typhimurium controls (adjusted odds ratio (aOR) 2.63, 95% confidence interval (CI) 1.06–6.48)) (neighbourhood controls (aOR 8.33, 95% CI 2.58–26.83)), wild frogs (aOR 3.65, 95% CI 1.32–10.07) and wild birds (aOR 6.93, 95% CI 2.29–21.00) were statistically associated with illness in multivariable analyses. S. Wangata was detected in dog faeces, wildlife scats and a compost specimen collected from the outdoor environments of cases’ residences. In addition, S. Wangata was detected in the faeces of wild birds and sea turtles in the investigation area. Genomic analysis revealed that S. Wangata isolates were relatively clonal. Our findings suggest that S. Wangata is present in the environment and may have a reservoir in wildlife populations in north-eastern NSW. Further investigation is required to better understand the occurrence of Salmonella in wildlife groups and to identify possible transmission pathways for human infections.

No abstract

The use of serum Cu concentration rather than plasma Cu concentration in the diagnosis of Cu responsive disease in cattle needs to be re-evaluated as does the way in which individual sample results are used in such tests.

Previous descriptive analysis of data collected from veterinary visits to lame cows in the Taranaki region of New Zealand between December 1995 and July 2007 showed an association between both breed and age and lesion type and site. However, that simple analysis had significant limitations as it did not take account of more than 2 factors at the same time and did not evaluate the effect of time (either year or season). This analysis was designed to overcome those limitations. First, correspondence analysis, a multivariate method of analysis, was used to simultaneously evaluate the relationship between the 3 most commonly recorded causes of lameness (i.e., white line disease, sole injury, and axial disease, all of which are diseases of the claw horn), and 4 groups of predictor variables: foot (front or hind), breed (Jersey or Friesian), age (heifer or cow), and claw (lateral or medial). Second, time series analysis was used to ascertain the effect of season on lesion type and identify the change over years in proportional morbidity. The correspondence analysis clearly separated the 3 diseases, showing that differences between these 3 diseases in their risk factors and their etiology. Each disease clustered with a group of predictor variables. White line disease was linked to lateral claw, hind foot, cow, and Friesian breed; sole injury was linked to heifer and medial claw; and axial disease to Jersey and front foot. As sole injury and axial disease are diseases that occur principally in cows at pasture, this is the first full analysis of risk factors for those diseases. The time series analysis further strengthened the conclusion that these 3 diseases have different risk factors, as, even in the strongly seasonal New Zealand system, significant differences in seasonality occurred between them. This analysis adds further to the data which show that claw horn diseases have different etiologies and need to be treated separately for both research purposes and for lameness management on-farm. This analysis is only a starting point; more research is required, particularly longitudinal studies, to better understand the differences in etiology between the main causes of lameness due to claw horn disease, especially in cows kept at pasture, so that we can better target prevention.

Subclinical infection or colonisation by S. equi subsp. zooepidemicus and S. dysgalactiae subsp. equisimilis occurs in dogs and further research on inter-species transmission and the pathogenic potential of these Lancefield group C streptococci is needed. Complete speciation of β-haemolytic streptococci should be recommended in clinical cases and the possible exposure to horses and their environment should be considered in epidemiological investigations.