Korean Hemorrhagic Fever
Where is Korean hemorrhagic fever found?
Hantaan virus, the agent of Korean hemorrhagic fever (KHF), is widely distributed throughout eastern Asia, particularly in China, Russia, and the Korean peninsula. Korean hemorrhagic fever was first noted during the Korean War in the 1950s, and it is now considered a major health concern in China and the Republic of Korea (ROK). Among the other agents of HFRS, Puumala virus is found primarily in Scandinavia, western Europe, and Russia; Dobrava virus is found primarily in the Balkans; and Seoul virus is distributed worldwide.
How prevalent is Korean hemorrhagic fever?
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Striped Field Mouse. Photo by Siga (CC BY-SA 3.0)
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Several hundred cases of HFRS (primarily KHF) occur in the ROK every year, mostly among civilians. While the vast majority of these cases are due to Hantaan virus, a small percentage may be attributed to both the Puumala and Seoul viruses. It is suspected that much larger numbers of KHF occur in North Korea. Since WWII, the largest outbreak of KHF in U.S. forces was in 1986. Among 3,754 Marines participating in a military training exercise in the ROK, 14 cases occurred: 10 were hospitalized; two of these died. In 1994, eight cases with one death occurred in U.S. Army personnel at an ROK training range. In 2005, two cases occurred in U.S. forces. It is estimated that 200,000 cases or more may occur in China per year.
How is Korean hemorrhagic fever transmitted?
Hantaviruses are carried and transmitted by rodents. Each hantavirus is associated with a single specific species of rodent (known as the reservoir). The reservoir for Hantaan virus is the striped field mouse, Apodemus agrarius. People become infected when they breathe in the aerosolized urine, droppings, or saliva of infected mice or the contaminated dust from their nests. Transmission may also occur when these infected materials are directly introduced into broken skin or onto mucous membranes of the eyes, nose, or mouth. Person-to-person transmission may occur, but is extremely rare. Reservoirs for the other agents of HFRS include the brown Norway rat (Rattus norvegicus) for Seoul virus; the bank vole (Clethrionomys glareolus) for Puumala virus; and the yellow-necked field mouse (Apodemus flavicollis) for Dobrava virus.
What are the symptoms of Korean hemorrhagic fever?
Symptoms of KHF usually develop suddenly within one to two weeks following exposure to infectious material, but may take up to two months in rare cases. Initial symptoms may include intense headaches, high fever, severe back and abdominal pain, nausea, vomiting, flushing of the face, inflammation of the eyes, and petechial rash (red-spotted rash due to hemorrhage of capillaries in the skin). These symptoms can then be followed by reduction in blood pressure, acute shock, dramatic decrease in urinary output, increased vascular leakage (hemorrhage of blood vessels), kidney failure, and death. The fatality rate for KHF is 5-15%. Complete recovery can take weeks to months. Of the four major hemorrhagic hantaviruses, Hantaan and Dobrava usually cause the most severe symptoms.
How is Korean hemorrhagic fever diagnosed?
Several factors are considered in the diagnosis of KHF: geographic distribution of the disease, an exposure to rodents, and the patient's clinical symptoms. Blood tests are used to confirm the diagnosis. These tests usually check for specific antibodies in the blood. Leptospirosis, dengue, and rickettsioses should be considered in the differential diagnosis.
What is the treatment for Korean hemorrhagic fever?
Supportive therapy is the standard of care for patients with KHF and other HFRS infections. Quiet bed rest and hospitalization are critical. It has been noted that the jostling and effect of lowered atmospheric pressures during airborne evacuation may be injurious to patients who are critically ill with KHF. Careful attention to fluid management (hydration and electrolyte levels), maintenance of correct oxygen and blood pressure levels, and appropriate treatment of any secondary infections are very important. Dialysis may be required to correct severe fluid overload and minimize the effects of shock and kidney failure. Some antiviral drugs may help in the early onset of HFRS. If you suspect that you may have been infected with Hantaan virus, or another HFRS virus, it is CRITICAL that you seek medical attention immediately.
How can Korean hemorrhagic fever be prevented?
There is no FDA-approved vaccine to prevent KHF. Therefore, rodent control is the primary strategy for preventing hantavirus infections, including KHF.
- Control rodent populations near human communities and bivouac sites.
- Store foods in rodent-proof containers; all garbage should be promptly buried, burned or discarded in sturdy trash containers with tight-fitting lids.
- Keep grass and shrubbery well-trimmed, leaf litter removed, and other rodent harborage moved 100 feet or as far as possible from bivouac sites and buildings.
- Do not disturb rodents or their burrows.
- Set snap traps or glue boards inside or close to buildings if there is evidence of rodent infestation, such as droppings or nests (look for small piles of shredded materials such as paper, insulation, twigs, or grass).
- Exclude rodents from homes and other buildings used by people. Seal all entry holes that are ¼ inch wide or wider with steel wool, cement, caulk, or wire screening.
- Avoid contact with rodent urine, droppings, saliva, nesting materials, and other contaminated debris.
- Avoid sleeping on bare ground; use elevated cots if available.
- Before occupying or cleaning abandoned or unused structures, open them up to air out for at least 30 minutes.
- Clean rodent-infested areas using the following safety precautions, recommended by the Centers for Disease Control and Prevention (CDC):
- Wear rubber, latex, vinyl, or nitrile gloves.
- Do not stir up dust by vacuuming or sweeping.
- Thoroughly wet contaminated areas and debris with a bleach solution or household disinfectant. A bleach solution can be made by mixing 1 ½ cups of household bleach in 1 gallon of water.
- Once everything is well dampened, remove contaminated materials with paper towels or rags and then mop or sponge the area with bleach solution or household disinfectant.
- Spray dead rodents and traps with bleach solution or disinfectant; then remove the rodent and place it in a plastic bag, along with all used cleaning materials. If desired, the dead rodent can be left in the trap and both disposed of in the bag. The bag should then be placed within a second plastic bag and sealed.
- Wash gloved hands with soap and water, or spray a disinfectant or bleach solution on gloves before taking them off. Wash hands with soap and warm water after taking off gloves (use a waterless alcohol-based hand rub when soap is not available and hands are not visibly dirty).
- In certain situations, where the contamination is extensive, specialized personal protective equipment will be required, to include a half-face respirator with N-100 (HEPA) cartridges or powered air purifying respirator (PAPR), coveralls, gloves, goggles, and non-permeable boots.
Where can I find more info on Korean hemorrhagic fever?
