Vertical transmission of the mother-mother rabies virus, a phenomenon that could keep the virus in wildlife reservoirs

Abstract

Introduction: The biological test established by the World Health Organization to isolate and amplify the rabies virus consists in inoculating lactating mice by intracranial route and detecting rabies signs for 21 days. Objective: To verify viral transmission in mothers of rabies virus-inoculated lactating mice. Method: Twenty-seven Mexican rabies virus isolates were inoculated by intracranial route in lactating mice, which were observed for 21 days. The mothers were observed for 60 days. The diagnosis was established by immunofluorescence in brain tissue. The virus was characterized by sequencing and with monoclonal antibodies. Results: All litters showed rabies at between 7 and 15 days post-inoculation (p. i.). Three of the 27 females (11 %) had developed rabies at days 33, 37 and 39 p. i. of their litters. Viral characterization showed that the mothers were infected with the same variant of their offspring, two of them stemming from hematophagous bat and one from dog. The liters that transmitted rabies to their mothers were nine individuals. Conclusions: In nature, the rabies virus could be preserved by transmission from neonates (more susceptible to contracting and amplifying the rabies virus) to their mothers.