VETSALUS NEWS BULLETIN: APRIL 2026

‘One Health’ is at the core of all we do at VetSalus and there are few issues closer to ‘One Health’ than zoonoses.  By definition a zoonosis is: “any disease or infection that is naturally transmissible from vertebrate animals to humans” and there may be as many as 200 of them, with the everpresent potential for new ones to emerge.

Origins of Covid

One zoonotic disease which needs no introduction is COVID-19 (caused by the SARS-CoV-2 virus.) The debate as to the origins of this virus, and hence its classification as a zoonosis, has been intense and somewhat political but a recent paper provides increasing evidence for the commonly held view: that COVID 19 originated in bats before spreading to humans at live food markets. The article, in a recent edition of Nature,was penned by 23 of the original 27 members of a panel appointed by the World Health Organisation (WHO) to investigate the origins of novel diseases, although this article is published independently. The fact that 4 members withheld their approval indicates that some potential controversy remains.

The paper presents the evidence around four possible hypotheses including a zoonotic origin and the possibilities of accidental or deliberate escape from a laboratory. The authors are firm in their conclusion that the most likely origin is a spillover event in or around the Huanan live animal market in December 2019, and no independent laboratory confirmation of earlier cases in other locations exist. 

No doubt the political aspects of the discussion will continue but the logic and probabilities of evidence based science will hopefully conclude the debate eventually.

Bird Flu and Cows 

Another virus which has attracted considerable attention in recent years is the H5N1 bird flu, particularly that which is infecting cows in parts of the USA. The VetSalus website has reported on this previously but a recent article suggests that the infection is waning and that its potential to become the next zoonotic pandemic is declining.

It appears that the virus is still circulating in California and Idaho and there is some confusion as to its prevalence in other states. Texas for example is listed as “affected”, despite no recent reports, because it has not complied with the national milk testing strategy.

Surveillance is confounded by data not being as available as previously, with at least one journal reporting that “critical data gaps remain that impede efforts to track virus movements in real time”. Funding for much fundamental science in the USA is currently under pressure and it would be a travesty if this potentially catastrophic virus slipped through the cracks formed by under funded science.

Ongoing work on the epidemiology of the disease has also led to some confusion. Chronically infected  ‘superspreading cows’ have been identified and, while milk was implicated as an important source of the virus in early investigations, the evidence for spread between cows at milking time, via milking machines, is still inconclusive. Other methods of spread, including potentially airborne transmission remain possibilities.Work on vaccination is also continuing.

In conclusion, there is growing evidence that this strain of the virus has been contained but confidence that this was so would be much higher if surveillance testing were more widespread and all data was publicly available.

Tuberculosis

This ancient bacteria struggles for attention in the face of challenges from trendier, more exotic diseases and it is all too easy to forget that, worldwide in 2024, nearly 11 million people fell ill with TB and the disease remains the world’s leading cause of death from a single infectious agent.

A recent review in The Lancet focused on human to human transmission with the numerous risk factors including malnutrition, overcrowding, smoking and immunosuppression.

But the zoonotic cause of the disease remains important in many countries with one source suggesting that as many as 150,000 cases annually can be traced to animal sources, mainly cattle. In 2017, the WHO published a major review of zoonotic TB, a publication that largely disappeared under the pressures of the COVID19 pandemic. The document traces a roadmap for TB control, stating that:

“The human burden of disease cannot be reduced without improving standards of food safety and controlling bovine TB in the animal reservoir.”

Ten priorities for effective control are listed, the fifth of which states simply “Improve Animal Health”.

While VetSalus and its growing group of consultants have a wide range of skills and knowledge that can be focused on many animal health issues, is it sometimes too easy to think of tuberculosis as a government or state veterinary service problem? If One Health is truly at the heart of VetSalus, every consultant should be aware of the global threat of TB and, where possible, contribute to its control. This is another area where well  informed veterinary advocacy can play an important role.

If you are interested in the work of VetSalus, you will find a wide range of articles and educational material on our web site: www.vetsalus.com