Congo virus

Congo virus

Congo-Crimean haemorrhagic fever was first observed in the Crimea by Russian scientists in 1944 and 1945. At that time it was established by studies in human volunteers that the aetiological agent was filtrable and that the disease in man was associated with the bite of the tick Hyalomma marginatum (The most important transmitters of the infection to man are species of the genus Hyalomma). The agent was detected in the larvae and in adult ticks, as well as in the blood of patients during the fever. This agent, presumably a virus, was not maintained in the laboratory and was lost.

Congo virus was first isolated in Africa from the blood of a febrile patient in Zaire in 1956.

The infection is usually transmitted to man by the bite of a tick, but an increasing number of cases have occurred among the medical and nursing staff caring for patients in hospital and in laboratory personnel carrying out investigations of these patients. In these cases the infection has apparently been acquired by contagion, particularly by contact with thepatient's blood or blood-contaminated specimens. Exposure to the blood of infected animals, especially cattle and sheep, has led to severe and often fatal infections.

The incubation period is 2 - 7 days. The onset of the illness is sudden, with fever, chills, severe muscular pains, headache, vomiting and pain in the epigastric and lumbar regions. A haemorrhagic state develops from the 3rd to the 5th day and manifests as petechial haemorrhages or purpura in the skin, and bleeding from the mucous membranes manifests as epistaxis, haemoptysis, haematemesis, melaena and haematuria. At this stage the conjunctivae are injected, the face is flushed and the tongue is dry, often coated with dry blood. The pulse is slow in the beginning, but with continuing loss of blood becomes fast and feeble; the blood pressure drops and the heart sounds become weak - clear signs of impending shock and vascular collapse. The liver is enlarged and tender and there is tenderness over the epigastrium and splenic region. In patients who recover, the temperature falls between the 10th and the 20th day and bleeding stops, but convalescence is prolonged up to 4 weeks or longer. In fatal cases, death from massive haemorrhage and cardiac arrest occurs, usually 7 - 9 days after the onset of the illness. Massive haemorrhage into the gastro-intestinal tract, with scattered haemorrhages into the viscera, is found at autopsy.

To prevent; Where mammal and tick infection is common agricultural regulations require de-ticking farm animals before transportation or delivery for slaughter. Personal tick avoidance measures are recommended, such as use of insect repellents, adequate clothing and body inspection for adherent ticks

Indian Scenario

By- January 20th, 2011, PTI

The National Institute of Virology (NIV), Pune, has confirmed the positive testing of Crimean-Congo Haemorrhagic Fever (CCHF) virus, identified for the first time in India, which has claimed three lives in Gujarat.

The virus at present appeared confined to Gujarat from where NIV had received the samples and the state government had started screening of all suspected cases, Dr A C Mishra, Director, NIV said, Dr Mishra said, Although the virus belongs to high risk category, there was no need for panic as its transmission is slow and can be arrested with isolation of patients in hospital, he said. "It is important that infections are prevented from spreading by isolating patients in hospitals and proper precautions are taken," Mishra added.

The Congo virus, which surfaced in Ahmedabad killed three persons including a doctor and nurse who treated the first victim - a woman from Kolat village in Sanand taluka of the district.