Guideline: Viral Haemorrhagic Fevers - Recognition and Management » Introduction
 

Introduction

 

Many infections, and even non-infectious diseases, can cause fever and a haemorrhagic state. It is important to distinguish these conditions from viral haemorrhagic fevers (VHFs) caused by the so-called formidable or Class 4 viruses. The VHFs have in common a propensity for person-to-person spread and high mortality rates, which necessitate that special  infection  control  measures  (isolation  precautions)  should  be  instituted  when managing suspected or confirmed cases of the diseases, and work with the viruses is permitted only in biosafety level 4 (BSL4) laboratories. However, not all of the viruses associated with VHFs are uniformly lethal or spread readily between humans: some less pathogenic viruses are placed in Class 4 in countries from which they are absent in order to exercise control over their possible introduction.

Many parts of the world have endemic VHFs, and modern travel has made it possible for introduced cases to occur virtually anywhere. The most common VHF in  Southern Africa is caused by the tick-borne Crimean-Congo haemorrhagic fever (CCHF or Congo fever) virus, and approximately 5-20 cases of the disease are diagnosed in South Africa each year. Rift Valley fever, a zoonotic disease of sheep and cattle, also occurs in our region, but human infections are generally seen in the context of major outbreaks of disease in livestock which occur at irregular intervals of many years when exceptionally heavy rains favour breeding of the mosquito transmitters of the virus, and human-to-human transmission has not been recorded. The most recent large outbreak in South Africa was in 2010. In addition, the growing tendency for severely ill patients from countries in tropical Africa to seek medical attention in South Africa is leading to increased risk that cases of Lassa, Marburg and Ebola haemorrhagic fevers may be imported inadvertently. Fatal nosocomial infections have occurred in South African hospitals in the past, and to avoid further tragedies health care workers should maintain high standards of infection control and biosafety awareness at all times, and all patient care facilities should institute contingency plans for dealing with VHF patients.

The present document, an updated version of guidelines first prepared in 1985, is intended as a guide to the recognition and management of suspected and confirmed cases, and prevention of nosocomial spread, of the indigenous African viral haemorrhagic fevers. The recommendations are not binding except where reference is made to legislation, statutory regulations, or agreed protocol for dealings between separate organizations and institutions, each of which should draft and implement protocols adapted to their own needs.