ProMED Summary #2

Hemorrhagic Fever with Renal Syndrome – Russia (07): Tatarstan

Archive Number 20081002.3106

Published Date 02-Oct-2008

The Republic of Tatarstan in Russia has experienced an increased incidence in Hemorrhagic Fever with Renal Syndrome (HFRS) for this year. The current report states the incidence for 2008 is seven times greater than reported for 2007. Between September 19 and 25, 2008, 29 confirmed or suspected cases were reported (International Society for Infectious Diseases [ISID], 2008a). This is in addition to outbreaks reported earlier this year. According to the Russian Epidemiological Surveillance System, there were 165 cases reported as of July. Cases increased from 65 on July 4 to 165 by July 22 (ISID, 2008b). Only one fatality has been reported at this time; generally, case fatality rates for HFRS range from 1% to 15%. Approximately 11% of total cases reported so far in 2008 have occurred in the capital city of Kazan. The majority of other cases have occurred in rural, forest areas of Tatarstan. The most recent outbreak of 29 cases has occurred in the following cities: Kazan (10), Naberezhnye Chenly (8), Nizhnekamiskiy (3), Almetievskiy (3), Sabinskiy (2), Kukmorshiy (1), and Bavlinskiy (1) (ISID, 2008a).

The Republic of Tatarstan is located in eastern Russia, about 800 kilometers southeast of Moscow (Department of Foreign Affairs to the President of the Republic of Tatarstan, 2008). As of 2002, the population of Tatarstan was 3,779,265, with an urban/rural population of 2,790,661 and 988,604, respectively. 

HFRS is endemic to Tatarstan and surrounding republics in eastern Russia (ISID, 2008a). Other geographic areas with endemic HFRS include Scandinavia, Western Europe, and the Balkans. The Puumala virus spread by the bank vole is the likely cause of the disease in Russia, Western Europe and Scandinavia. The Dobrava virus is found in the Balkans and the Seoul virus may occur worldwide. All viruses are part of the Hantavirus classification. Hantavirus is transmitted to humans by vector rodents such as voles and field mice (Centers for Disease Control and Prevention [CDC], 2005).

According to research conducted by Alla Bernshtein and colleagues of the Chunakov Institute in Moscow, natural increases and decreases of the bank vole population occur every three to four years. In years of higher vole populations, the incidence of human HFRS increases (ISID, 2008c).

Experts speculate a number of factors have contributed to the rise above endemic levels of human HFRS in Tatarstan and surrounding regions. First, an increase in the bank vole population may be a result of climate changes. Less harsh winters and warmer summers allow for better access to food sources for the rodents.  Second, the new capitalistic Russia has resulted in increased construction of homes in rural forest areas. Humans have invaded the natural habitat of forest rodents. This has increased the potential for contact between the habitats of bank voles and humans. City dwellers tend to visit their countryside homes during the summer months of June through August. The majority of HFRS cases are reported during these summer vacation months (ISID, 2008b).

As mentioned previously, Hantavirus is spread to humans by rodents. As reported by the CDC (2005), infection occurs when humans encounter “aerosolized urine, droppings, saliva of infected rodents or after exposure to dust from their nests.” Infection may also occur through open wounds, mucous membranes, rodent bites, and in rare cases through person-to-person contact. Most cases occur in individuals older than 15 years old, as children under the age of 15 often only show subclinical symptoms of HFRS.

The incubation period of HFRS is one to two weeks. The CDC (2005) lists the following symptoms: severe headaches, back and abdominal pain, fever, chills, nausea and blurred vision. Fever, hemorrhage, and renal insufficiency are hallmarks of advanced disease. The disease generally progresses through five stages: 1) fever lasting four to six days, 2) low blood pressure lasting a few hours to 2 days, 3) decreased production of urine for three to six days, 4) diuretic stage lasting two to three weeks, and 5) recovery that may take three to six months. HFRS infection is confirmed by clinical symptoms, serological testing, microscopic inspection for Hantavirus antigen, or presence of Hantavirus RNA in blood and tissue samples. Depending on the patient’s fluid and electrolyte status, renal dialysis may be warranted. Patients may be required to follow sodium and fluid restricted diet during the oliguric stage followed by a liberal fluid intake during the diuretic stage. In addition, the administration of the intravenous antiviral drug, Ribavirin, lessens the disease severity and improves survival (Bhimma, Sairam, & Travis, 2008).

The Puumula virus carried by the bank vole is implicated in the current outbreak of HFRS described above. Bhimma et al. (2008) contend that prevention of HFRS starts with environmental control of rodent populations near human housing communities and structures. Recommendations for prevention include taking precautions such as wearing rubber gloves while cleaning areas contaminated with rodent droppings or urine, avoid stirring up dust in rodent areas, and using a bleach solution with disposable cleaning towels. Storing food and disposing of trash properly may also prevent rodents from interacting with human habitats. Humans should take precautions if sleeping outdoors, working on farm areas or handling hay where rodents may have built nests (Bhimma et al., 2008).

In summary, the Puumula virus is a vector carried virus that falls within the Hantavirus family. It is endemic to eastern Russia where rodent populations thrive in rural forest areas. Infection leads to HFRS in humans. Symptoms take one to two weeks to appear, with initial symptoms of headaches and back pain that may progress to acute renal failure. The survival rate is high for infected populations although recovery may take several months. The Puumula virus is recognized as one of the less severe forms in the Hantavirus family. Controlling rodent populations and public education of risks are keys to the prevention of HFRS.

                                                       

 

References

Bhimma, R., Sairam, V. K., & Travis, L. (2008). Hemorrhagic fever with renal failure syndrome. Retrieved from http://www.emedicine.com/ped/TOPIC968.HTM 

Centers for Disease Control and Prevention. (2005). Hemorrhagic fever with renal syndrome. Retrieved from http://www.cdc.gov/ncidod/dvrd/spb/mnpages/dispages/hfrs.htm 

Department of Foreign Affairs to the President of the Republic of Tatarstan. (2008). Official web-site republic of Tatarstan: Geographical location. Retrieved from http://www.tatar.ru/index.php?DNSID=7285d20214ab4a8019cb26275358e482&node_id =797 

International Society for Infectious Diseases. (2008a). Hemorrhagic fever with renal syndrome

– Russia (07): (Tatarstan). Retrieved from

http://www.promedmail.org/pls/otn/f?p=2400:1001:625313785652199::NO::F2400_P10

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International Society for Infectious Diseases. (2008b). Hemorrhagic fever with renal syndrome – Russia (04): (Tatarstan). Retrieved from http://www.promedmail.org/pls/otn/f?p=2400:1001:625313785652199::::F2400_P1001_ BACK_PAGE,F2400_P1001_ARCHIVE_NUMBER,F2400_P1001_USE_ARCHIVE:10 01,20080722.2226,Y 

International Society for Infectious Diseases. (2008c). Hemorrhagic fever with renal syndrome – Russia (05): (Tatarstan, Udmurtia). Retrieved from http://www.promedmail.org/pls/otn/f?p=2400:1001:625313785652199::::F2400_P1001_ BACK_PAGE,F2400_P1001_ARCHIVE_NUMBER,F2400_P1001_USE_ARCHIVE:10 01,20080730.2337,Y