Researchers recently identified a fatal case of systemic campylobacteriosis in a wild American crow nestling in San Diego, CA. This significant finding, published in the Journal of Veterinary Diagnostic Investigation, reveals the presence of a novel pathogen, Campylobacter molothri. This bacterium caused severe encephalitis and sepsis in the young bird. Consequently, the case highlights the critical importance of advanced molecular techniques in identifying emerging pathogens that could impact wildlife and public health.

The Clinical Impact of Systemic Campylobacteriosis

The postmortem examination revealed a markedly underweight chick with no fat stores. Histologic analysis showed lymphocytic vasculitis in the brain and lymphohistiocytic meningoencephalitis. These areas of inflammation were closely associated with myriad argyrophilic, curved bacilli. Furthermore, clinicians observed severe pectoral myositis and evidence of systemic sepsis, including pancarditis and hepatitis.

Advanced Molecular Identification of C. molothri

Using third-generation sequencing and conventional PCR, scientists identified the bacteria as closely related to Campylobacter molothri. This species belongs to the Campylobacter genus, which contains many well-known human pathogens. While C. jejuni typically causes gastroenteritis, this novel finding suggests that some species may induce more severe systemic infections in specific hosts. Therefore, continuous surveillance of wild bird populations remains essential for understanding the evolutionary landscape of these pathogens.

One Health Implications and Zoonotic Risks

The discovery of a novel Campylobacter species in a common urban bird like the American crow raises questions about zoonotic potential. Historically, wild birds serve as reservoirs for various Campylobacter strains. Although most infections in birds are asymptomatic, this case demonstrates that certain species can cause significant pathology. Monitoring such events helps identify potential threats to both animal and human health before they cross species barriers.

Frequently Asked Questions

What is Systemic Campylobacteriosis?

It refers to a severe infection where Campylobacter bacteria spread from the primary site to the bloodstream and multiple organs, such as the brain and heart.

Is Campylobacter molothri a threat to humans?

Currently, researchers have identified C. molothri primarily in wild birds. However, many species in the Campylobacter genus are known zoonotic pathogens that cause significant human disease.

How was this new pathogen identified?

Diagnostic pathologists used advanced tools like third-generation sequencing and PCR to pinpoint the bacterial DNA from tissue samples taken during the autopsy.

Disclaimer: This content is for informational and educational purposes only. It does not constitute medical advice or establish a doctor-patient relationship. Refer to the latest local and national guidelines for clinical practice.

References

1. Nakagun S et al. Systemic campylobacteriosis in an American crow chick. J Vet Diagn Invest. 2026 Feb 13. doi: 10.1177/10406387261418325. PMID: 41685534.


2. Silva J et al. Campylobacteriosis: the most commonly reported zoonotic foodborne illness. Nature Reviews Gastroenterology & Hepatology. 2011;8(12):661-71.