Mouse Fever on the Rise in Russia

Hemorrhagic fever with renal syndrome [HFRS] is referred to colloquially as "mouse fever" because rodents are the principal vector. The human population usually becomes infected by inhaling dust in buildings where rodents are present.

In comparison with last year [2012], the incidence of mouse fever has decreased. During 10 months of 2013, 209 cases of "mouse" fever were recorded in the region, 6.5 per 100 000 inhabitants.. In the last 10 years, the highest incidences were recorded in 2003 (500 cases or 15.16 per 100 000 population), in 2008 (607 cases or 19.4 per 100 000 population), and 2012 (813 cases or 25.3 per 100 000 population). The source of infection and the reservoir host of HFRS are wild rodents.The largest number of cases -- 38 in total -- were recorded in Vladivostok.

Symptoms of HFRS usually develop within 1 to 2 weeks after exposure to infectious material, but in rare cases, they may take up to 8 weeks to develop. Initial symptoms begin suddenly and include intense headaches, back and abdominal pain, fever, chills, nausea, and blurred vision. Individuals may have flushing of the face, inflammation or redness of the eyes, or a rash. Later symptoms can include low blood pressure, acute shock, vascular leakage, and acute kidney failure, which can cause severe fluid overload. The severity of the disease varies depending upon the virus causing the infection. Hantaan and Dobrava virus infections usually cause severe symptoms, while Seoul, Saaremaa, and Puumala virus infections are usually more moderate. Complete recovery can take weeks or months.

Supportive therapy is the mainstay of care for patients with hantavirus infections. Care includes careful management of the patient’s fluid (hydration) and electrolyte (e.g., sodium, potassium, chloride) levels, maintenance of correct oxygen and blood pressure levels, and appropriate treatment of any secondary infections. Dialysis may be required to correct severe fluid overload. Intravenous ribavirin, an antiviral drug, has been shown to decrease illness and death associated with HFRS if used very early in the disease.

Depending upon which virus is causing the HFRS, death occurs in less than 1% to as many as 15% of patients. Fatality ranges from 5-15% for HFRS caused by Hantaan virus, and it is less than 1% for disease caused by Puumala virus.

In the absence of adequate treatment, the outcome of infection may be severe and a serious threat to life. Severe forms of the disease are a serious threat to human life, according to the Samara Region Rospotrebnadzor organization.

source; ProMEDmail & CDC

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