Korean Hemorrhagic Fever

(Also known as Epidemic Hemorrhagic Fever and Hemorrhagic Fever with Renal Syndrome)

By Stella Lee RN, Kyung Hee University, Seoul Gary Podolsky MD University of Manitoba

Cause

It's an acute febrile disease caused the infection of Hantaan virus (or Seoul virus). This is a separate but related disease from that of the Hanta virus known in North America.

Epidemiological Features

World wide distribution: 150,000~200,000 people are hospitalized every year and more than half of them occur from China, Korea, Japan, Russia, Finland, Sweden, and the Balkan Peninsula.

In Korea: It occurred 100 people per year from 1995 to 1998. It increased by 200 people after 1998. It occurred frequently in Kyonggi, Seoul and Kyongbuk provinces.

Occurrence begins in October and with a peak apex in November, until December and until January. It occurred frequently in people aged 40-49 years old but also in those 20-39 years of age and children.

The carrier of the pathogen are rodents the wild rat ( Apodemus agrarius ). Infected Apodemus agrarius are responsible for transmission in most cases (71-90%) Contagion is through infected rat fluids (urine and feces, saliva) and with direct contact of rat faeces (aerosolized )to lungs or with a wound (cutaneous). High-risk groups include men who do outdoor activities, military personnel, farmer, and lab technicians exposed to infected animals.

Symptoms

The incubation period is 1-3 weeks, and then patients become feverish with the hemorrhage and renal lesions occurring later.

The clinical course is:

Febrile phase (3-5 days) which is characterized by sudden onset fever, malaise and severe headache. A red rash develops on the face and trunk along with conjunctival hyperemia, ecchymosis, thrombocytopenia and proteinuria.

Hypotensive phase (3-6 days), is characterized by persistence of generalized symptoms and anxiety. Hypotension, delirium, hematemesis, coma may present. Severe proteinuria and frequent urination.Other laboratory features include thrombocytopenia, leukocytosis, and hematuria and increased hematocrit.

Oliguric phase (3-5 days), is characterized by nausea, vomiting, oliguria, naturemia, electrolyte imbalance, hyperkalemia, and hypertension. Occasional cerebral and pulmonary edema. Purpura are noted. Gastrointestinal hemorrhage may be noted.

Diuretic phase (7-14 days) involves a partial recovery of renal function with polyuria. Severe dehydration and hypovolemic shock is a danger. Death from pulmonary complication may result.

Recovery phase (3-6 weeks) follows the 5 phases. Patients may still have polyuria or nocturia and anemia.

Atypical cases may show variations from the 5 phases and may not involve all symptoms.

Diagnosis

The diagnosis is made with a combination of the history, clinical symptoms, lab data and the progression of the disease. It can be confirmed with IGM antibody test, ELISA and Hantdia kit (available in Korea).

Differential diagnoses include acute G-I disorders, Hepatitis, Meningococcal sepsis, acute nephritis, Central Nerve System disorders, other febrile and viral hemorrhagic fever infections

Treatment

Treatment is individualized for each of the phases of the progression of the disease.

Bed Rest is the most important thing, it gives the symptomatic therapy against pain and vomiting Hydration is maintained with 10% Dextrose solution. If patients have low blood pressure they may be given low salt serum albumin or plasma expanders (Reomacrodex). Oliguria or anuria patient treatment follows the same for renal failure. When the hemorrhagic tendency is serious observation for pulmonary hemorrhage is important. During the Oliguric phase patients are restricted their intake of potassium. In the Diuretic phase careful attention to adequate hydration and potassium is important. It has been reported that Ribavirin decreases a mortality rate.

Prognosis

With no treatment, more than 15% mortality occurs. With treatment mortality is less than 5%.

Patient and Contact person Management

Patient care: Does not need isolation

Contact person care: No isolation.

Prevention

Immunization with the inactivated Hantavirus vaccine inoculation is recommended for those frequently exposed to environments which can be contaminated by the Hantaan virus or for persons who belongs in the high risk groups.

The vaccine is given in 3 doses: an initial inoculation vaccine 0.5 ml followed by two boosters at one and 12 months. The vaccine may be given subcutaneously or intra muscularly.

There are no guidelines for further boostings.

Ms Lee has worked as a Internal Medicine nurse at Seoul National University hospital in Korea with Korean Hemorrhagic fever and now works in Canada as a Travel Nurse with Dr Podolsky at the Skylark Medical clinic in Winnipeg Manitoba, Canada.