2--c-methylcytidine and Diarrhea

Norovirus outbreaks of acute gastroenteritis are highly prevalent, extensive and can disturb the functioning of health institutions, leading to the closure of hospital wards and causing life-threatening infections in long-term care facilities. There is no vaccine available; hence there is a pressing need for antivirals for the treatment (in immunodeficient patients) and prophylaxis of norovirus infections. We explored in a mouse model whether an inhibitor of norovirus replication can prevent/reduce transmission of the virus.. We reported recently that the viral polymerase inhibitor 2'-C-methylcytidine (2CMC) efficiently protects against murine norovirus (MNV)-induced diarrhoea and mortality in mice. Here, we established an MNV-transmission model, determined the 50% infectious dose and assessed the ability of an antiviral molecule to prevent or reduce transmission of (murine) norovirus when given either to the infected (seeder) mice or to the uninfected (sentinel) mice.. A robust norovirus transmission model was established using genogroup V (murine) norovirus in AG129 mice. The 50% infectious dose was determined to be ∼ 270 CCID50 (50% cell culture infectious dose). Treatment of infected mice with 2CMC reduced viral shedding and markedly reduced transmission to uninfected sentinels. Also, prophylactic treatment of sentinels with 2CMC resulted in protection against infection with MNV.. These findings constitute an important first step towards developing an efficient prophylaxis for the control of norovirus outbreaks.

Topics: Animals; Antiviral Agents; Caliciviridae Infections; Chemoprevention; Cytidine; Diarrhea; Disease Models, Animal; Female; Male; Mice; Norovirus; Survival Analysis

Human noroviruses are a major cause of food-borne illness, accountable for 50% of all-etiologies outbreaks of acute gastroenteritis (in both developing and developed countries). There is no vaccine or antiviral drug for the prophylaxis or treatment of norovirus-induced gastroenteritis. We recently reported the inhibitory effect of 2'-C-methylcytidine (2CMC), a hepatitis C virus polymerase inhibitor, on the in vitro replication of murine norovirus (MNV). Here we evaluated the inhibitory effect of 2CMC on in vitro human norovirus replication through a Norwalk virus replicon model and in a mouse model by using AG129 mice orally infected with MNV. Survival, weight, and fecal consistency were monitored, and viral loads in stool samples and organs were quantified. Intestines were examined histologically. 2CMC reduced Norwalk virus replicon replication in a dose-dependent manner and was able to clear cells of the replicon. Treatment of MNV-infected AG129 mice with 2CMC (i) prevented norovirus-induced diarrhea; (ii) markedly delayed the appearance of viral RNA and reduced viral RNA titers in the intestine, mesenteric lymph nodes, spleen, lungs, and stool; (iii) completely prevented virus-induced mortality; and (iv) resulted in protective immunity against a rechallenge. We demonstrate for the first time that a small-molecule inhibitor of norovirus replication protects from virus-induced disease and mortality in a relevant animal model. These findings pave the way for the development of potent and safe antivirals as prophylaxis and therapy of norovirus infection.

Topics: Animal Structures; Animals; Antiviral Agents; Body Weight; Caliciviridae Infections; Cytidine; Diarrhea; Disease Models, Animal; Feces; Female; Male; Mice; Norovirus; Norwalk virus; RNA, Viral; Survival Analysis; Viral Load; Virus Replication