Fourth imported rabies case since the eradication of rabies in Japan in 1957

β-d-N4-hydroxycytidine, a metabolite of molnupiravir, exhibits in vitro antiviral activity against rabies virus

Rabies is a fatal neurological disorder caused by rabies virus (RABV) infection. Approximately 60,000 patients die from rabies annually, and there are no effective treatments for this disease. Nucleoside analogs are employed as antiviral drugs based on their broad antiviral spectrum, and certain nucleoside analogs have been reported to exhibit anti-RABV activity. The nucleoside analog β-d-N4-hydroxycytidine (NHC) has antiviral effects against a range of RNA viruses. Molnupiravir (MPV), a prodrug of NHC, is clinically used as an oral antiviral drug for coronavirus infections. Despite its broad-spectrum activity, the antiviral activity of NHC against RABV remains unclear. In this study, we reveal that NHC exhibits comparable in vitro anti-RABV activity as ribavirin and favipiravir (also known as T-705) with a 90% effective concentration of 6 μM in mouse neuroblastoma cells. NHC reduced viral loads in neuronal and nonneuronal cells in a dose-dependent manner. Both laboratory and field RABVs (fixed and street strains, respectively) were susceptible to NHC. However, no increase in survival or reduction in viral titers in the brain was observed in RABV-infected mice treated prophylactically with MPV. These findings highlight the potential and challenges of NHC in the treatment of RABV infection.

Reverse genetic approaches allowing the characterization of the rabies virus street strain belonging to the SEA4 subclade

Rabies virus (RABV) is the causative agent of rabies, a lethal neurological disease in mammals. RABV strains can be classified into fixed strains (laboratory strains) and street strains (field/clinical strains), which have different properties including cell tropism and neuroinvasiveness. RABV Toyohashi strain is a street strain isolated in Japan from an imported case which had been bitten by rabid dog in the Philippines. In order to facilitate molecular studies of RABV, we established a reverse genetics (RG) system for the study of the Toyohashi strain. The recombinant virus was obtained from a cDNA clone of Toyohashi strain and exhibited similar growth efficiency as the original virus in cultured cell lines. Both the original and recombinant strains showed similar pathogenicity with high neuroinvasiveness in mice, and the infected mice developed a long and inconsistent incubation period, which is characteristic of street strains. We also generated a recombinant Toyohashi strain expressing viral phosphoprotein (P protein) fused with the fluorescent protein mCherry, and tracked the intracellular dynamics of the viral P protein using live-cell imaging. The presented reverse genetics system for Toyohashi strain will be a useful tool to explore the fundamental molecular mechanisms of the replication of RABV street strains.

Human Rabies during the COVID-19 Pandemic: Insights into Rabies Worldwide and Brazil

Human Rabies (HR) is a fatal zoonotic disease caused by lyssaviruses, with the rabies virus (RABV) identified as the causative agent. While the incidence of HR transmitted by dogs has decreased in Latin America, there has been a corresponding rise in transmission via wild animals. Given the lack of effective treatments and specific therapies, the management of HR relies on the availability of post-exposure prophylaxis and animal control measures. This review examines the dynamics and spread of HR during the global pandemic.

Epidemiological Associations between Rabies Vaccination and Dog Owner Characteristics

BACKGROUND

The annual rabies vaccination coverage in dogs among 47 prefectures in Japan has been reported to range from 42.3% to 92.4%, and the overall coverage has been steadily declining. Given the presence of unregistered dogs and the small number of stray dogs, the true vaccination coverage is likely to be even lower.

METHODS

We conducted a cross-sectional survey of dog owners to identify the owner characteristics associated with dog rabies vaccination. People in Japan who currently own dogs were recruited and answered a questionnaire consisting of four sections: (i) demographic characteristics, (ii) education history associated with medicine, (iii) factors related to veterinary services, and (iv) dog characteristics.

RESULTS

A total of 534 dog owners covering 629 dogs were surveyed. Vaccination within the prior 12 months was the major outcome (56.1%). The associated variables were (a) owner education level, (b) knowledge about mandatory vaccination, (c) having a family veterinary clinic, (d) frequency of visiting a veterinary clinic, and (e) having ever been advised to vaccinate their dog.

CONCLUSIONS

Although causality cannot be implied, our findings indicate improving owners' knowledge about mandatory vaccination, facilitating attachment to a veterinary clinic, and veterinarians providing vaccination advice might increase the uptake of dog rabies vaccination. The finding in Japan did not deviate from Asian and African countries with rabies, and the sample estimate of annual vaccination coverage was lower than the reported estimate among registered dogs.

Human rabies control in the era of post-COVID-19: a call for action

Following the COVID-19 pandemic, there has been a sharp increase in rabies cases and deaths. Rabies outbreaks are being reported worldwide. Multiple disruptions in Rabies control occurred during the pandemic, significantly affecting lower-income countries. Countries need to develop specific action plans to become 'rabies free' by 2030.