Section 7 Hemorrhagic Fever with Renal Syndrome
Introduction of HFRS
Hemorrhagic Fever with Renal Syndrome（HFRS）is a natural focal disease caused by the virus in the Hantaviruses of the Bunyavirus family of Arbovirus. The main infectious source of TypeⅠ HFRS is Apodemus agrarius，the infected area of which has a characteristic of distributing along the water. The main infectious source of Type Ⅱ HFRS is Rattus norvegicus，the geographical distribution was not obvious. The transmission routes of HFRS include animal-borne，mite-borne and vertical transmission. In Guangdong，HFRS can be onset throughout the year，reaching peak in autumn and winter，usually from November through next February. Human are widely susceptible，especially for 20-50 years old adult males. Men are more frequently infected than women with a ratio of 2.5︰1～3.1︰1，but in recent years，with the change of production mode and the increase of population mobility，the ratio of female patients has risen.
The incubation period of HFRS is usually 7-14 days，with the shortest being 3 days and longest 60 days. HFRS has complicated clinical manifestations，which are significantly different because of the various strains of the virus，the timely treatment and the appropriate measures. Typical disease course includes five phases as fever，hypotension，oliguria，diuresis and recovery. Hypotension and oliguria in milder cases is not obvious，accounting for more than 60% of total cases. In severe cases，the former two or three phases can take place repeatedly.
1. Clinical phases of typical patients
（1）Fever phase：
This phase is characterized by toxemia lasting 5-7 days. The symptoms occur acutely，manifesting chilly and fever. Body temperature is usually around 38-41℃，predominantly taking forms of continued fever or remittent fever. Other symptoms include headache，back pain，orbital pain，dizziness，malaise，poor appetite，nausea and vomiting，abdominal pain and diarrhea. Acute complexion may occur which is characterized by obvious congestion in skin，red appearance in face，neck，upper chest，resembling heavy drunk. Edema may develop in eyelid and conjunctiva. 2 days after the onset，hemorrhagic spots may take place in skin and mucous membranes，mostly clustering in conjunctiva，upper jaw and armpits. Percussion pain in renal area is obvious and touniguer test can be positive.
（2）Hypotension phase：
It usually occurs in day 5-8 during the course of the disease. With body temperature stepping down and pulse becoming faster，the blood pressure begins to fluctuate. When the SBP is lower than 90mmHg（12kPa），the patient enters into hypotension phase，which usually lasts 1-4 days. The symptoms of fever phase are still persistent and hypothermia becomes a hallmark of this phase.
（3）Oliguria phase：
It usually occurs in day 6-8 during the course of the disease and generally lasts for 2-5 days. When the amount of urine is less than 1 000ml within 24 hours，it’s called oliguria trend；when the amount of urine is less than 500ml within 24 hours or less than 30ml/h，called oliguria and when the amount of urine is less than 50ml within 24 hours，called anuria. In this phase，patient becomes extremely exhausted，the symptoms such as headache，dry mouth and thirst，nausea and vomiting deteriorate. Severe patients show dysphoria，confusion，convulsion and coma. Patient in this phase has the clinical manifestations of uremia，acidosis and electrolyte disturbance obviously.
（4）Diuresis phase：
It usually takes place in day 10-12 during the course of the disease lasting 7-14 days. When the amount of urine within 24 hours exceeds 3 000ml，it’s called diuresis.
（5）Recovery phase：
Since 3rd-4th week in the course of the disease. The renal function is gradually improved，the amount of urine approaches to normal level，the symptoms disappear and physical ability begins to recover.
2. Treatment
Comprehensive treatment is recommended，which includes early discovery，early rest，early treatment and administering therapies in nearest setting. Furthermore，critical situations such as shock，acidosis and urinemia，severe hemorrhage and infection also should be paid attention.
3. Preventive measures
It includes rodent control，mites prevention，vaccination，surveillance strengthen，personnel training strengthen，publicity and education work strengthen. Besides，the prevention of hemorrhagic fever in special environment should also be attached great importance.
肾综合征出血热流行病学个案调查表
Epidemiological Questionnaire for Cases of Hemorrhagic Fever with Renal Syndrome
Questionnaire
（本节编者-李意兰 本节核对-孙艺）