Congo CCHF - virus – Know the Treatment and
How to prevent and control spread of Congo or CCHF Virus,Infection
What is a viral hemorrhagic fever?
A viral hemorrhagic fever is a viral disease, which has a tendency to disrupt
the clotting of the blood, so that patients may develop uncontrolled bleeding.
Usually fever, body aches, and other flu-like symptoms also are seen.
Many common diseases can resemble viral hemorrhagic fever, but the term is
reserved for a particular group of diseases associated with a high death
(fatality) rate.
In addition to CCHF they include Lassa fever, Rift Valley
fever, Alkhumra, Omsk hemorrhagic fever, Kyasanur forest disease,
Argentine, Bolivian, Brazilian, and Venezuelan hemorrhagic fevers (caused
by Junin, Machupo, Sabia, and Guanarito viruses, respectively), and
Marburg and Ebola hemorrhagic fevers.
The National Institute of Virology (NIV) 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 geographic range of CCHF virus is the most extensive among the tickborne viruses that affect human health, and the second most widespread of all medically important arboviruses, after dengue viruses
CCHF has become one of the most geographically widely distributed tick-borne diseases in the world; the disease, or the presence of the virus, has been reported from at least 31 countries in Africa, Asia, southeast Europe, and the Middle East.
Where does the CCHF virus come from?
A: The virus is transmitted mainly by Hyalomma ticks, adults of which have dis-
tinctive brown and white bands on their legs.
The virus can remain in the ticks for long periods, and even pass through the eggs to infect the next generation of ticks.
Immature Hyalomma ticks (larvae and nymphs) feed on ground-frequenting
(or ground-feeding) birds (guinea fowl, partridges, rooks) and small mammals
up to the size of hares.
Adult Hyalomma ticks feed on livestock such as cattle,sheep, and goats, as well as on wild animals such as antelope, wild boar, and ostriches.
Animals bitten by infected ticks do not develop the disease, but can circulate
the virus in their blood for a few days, up to 1 week, and thereafter become
immune to further infection.
Non infected ticks become infected if they feed on the animals during the short period when virus is in circulation, thus ensuring that the virus is perpetuated.
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.
The mortality rate from CCHF is approximately 30%, with death occurring in the second week of illness.
In those patients who recover, improvement generally begins on the ninth or tenth day after the onset of illness.
Crimean-Congo haemorrhagic fever (CCHF) is a viral haemorrhagic fever of the Nairovirus group.
The disease was first described in the Crimea in 1944 and given the name Crimean haemorrhagic fever.
In 1969 it was recognized that the pathogen causing Crimean haemorrhagic fever was the same as that responsible for an illness identified in 1956 in the Congo and linkage of the 2 place names resulted in the current name for the disease and the virus. CCHF is a severe disease in humans, with a high mortality rate.
The virus which causes CCHF is a Nairovirus, a group of related viruses forming one of the five genera in the Bunyaviridae family of viruses.
All of the 32 members of the Nairovirus genus are transmitted by argasid or ixodid ticks, but only three have been implicated as causes of human disease:
During the summers of 1944 and 1945 over 200 cases of an acute, hemorrhagic, febrile illness occurred in Soviet troops rescuing the harvest following the ethnic cleansing of the Crimean Tatars.
Soviet scientists first identified the disease they called Crimean hemorrhagic fever in 1944 and established its viral etiology by passage of the virus through human "volunteers"
CCHF or Congo reservoirs and vectors –
A reservoir is a place or a zone where a supply is kept in store.
Reservoir refers to a carrier of a virus or parasite for which they are not pathogenic.
Pathogenic means Capable of causing disease or Originating or producing disease.
Vector means any agent (person or animal or microorganism) that carries and transmits a disease; "mosquitos are vectors of malaria and yellow fever"
1.
The CCHF virus may infect a wide range of domestic and wild animals. Many birds are resistant to infection, but ostriches are susceptible and may show a high prevalence of infection in endemic areas. Animals become infected with CCHF from the bite of infected ticks.
2.
A number of tick genera are capable of becoming infected with CCHF virus, but the most efficient and common vectors for CCHF appear to be members of the Hyalomma genus.
3.
The most important source for acquisition of the virus by ticks is believed to be infected small vertebrates on which immature Hyalomma ticks feed.
Once infected, the tick remains infected through its developmental stages, and the mature tick may transmit the infection to large vertebrates, such as livestock. Domestic ruminant animals, such as cattle, sheep and goats, are viraemic (virus circulating in the bloodstream) for around one week after becoming infected.
How the Humans get infected by Congo or CCHF virus?
Humans who become infected with CCHF acquire the virus from direct contact with blood or other infected tissues from livestock during this time, or they may become infected from a tick bite.
The majority of cases have occurred in those involved with the livestock industry, such as agricultural workers, slaughterhouse workers and veterinarians.
The virus is transmitted to humans by the bite of Ixodid tick (mostly of the Hyalomma genus) or by contact with blood or tissues from human patients or infected livestock
The length of the incubation period for the illness appears to depend on the mode of acquisition of the virus.
Following infection via tick bite, the incubation period is usually one to three days, with a maximum of nine days.
The incubation period following contact with infected blood or tissues is usually five to six days, with a documented maximum of 13 days.
What are symptoms of Congo once it is acquired by Human?
Onset of symptoms is sudden, with fever, myalgia (aching muscles), dizziness, neck pain and stiffness, backache, headache, sore eyes and photophobia (sensitivity to light).
There may be nausea, vomiting and sore throat early on, which may be accompanied by diarrhoea and generalized abdominal pain.
Over the next few days, the patient may experience sharp mood swings, and may become confused and aggressive.
After two to four days, the agitation may be replaced by sleepiness, depression and lassitude, and the abdominal pain may localize to the right upper quadrant, with detectable hepatomegaly (liver enlargement).
Other clinical signs which emerge include tachycardia (fast heart rate), lymphadenopathy (enlarged lymph nodes), and a petechial rash (a rash caused by bleeding into the skin), both on internal mucosal surfaces, such as in the mouth and throat, and on the skin.
The petechiae may give way to ecchymoses (like a petechial rash, but covering larger areas) and other haemorrhagic phenomena such as melaena (bleeding from the upper bowel, passed as altered blood in the faeces), haematuria (blood in the urine), epistaxis (nosebleeds) and bleeding from the gums.
There is usually evidence of hepatitis. The severely ill may develop hepatorenal (i.e., liver and kidney) and pulmonary failure after the fifth day of illness.
What is the procedure to Diagnosis of CCHF or Congo Virus?
Diagnosis of suspected CCHF is performed in specially-equipped, high biosafety level laboratories. IgG and IgM antibodies may be detected in serum by enzyme-linked immunoassay (the "ELISA" or "EIA" methods) from about day six of illness. IgM remains detectable for up to four months, and IgG levels decline but remain detectable for up to five years.
Patients with fatal disease do not usually develop a measurable antibody response and in these individuals, as well as in patients in the first few days of illness, diagnosis is achieved by virus detection in blood or tissue samples.
There are several methods for doing this.
The virus may be isolated from blood or tissue specimens in the first five days of illness, and grown in cell culture.
Viral antigens may sometimes be shown in tissue samples using immunofluorescence or EIA.
More recently, the polymerase chain reaction (PCR), a molecular method for detecting the viral genome, has been successfully applied in diagnosis.
Treatment for Congo or CCHF –
General supportive therapy is the mainstay of patient management in CCHF. Intensive monitoring to guide volume and blood component replacement is required.
The antiviral drug ribavirin has been used in treatment of established CCHF infection with apparent benefit.
Both oral and intravenous formulations seem to be effective.
The value of immune plasma from recovered patients for therapeutic purposes has not been demonstrated, although it has been employed on several occasions.
Ribavirin aerosol is antiviral drug that could be also used in viral hemorrhagic fever syndromes. Besides Crimean-Congo hemorrhagic fever (CCHF), it is used in Lassa fever
How to prevent and control spread of Congo or CCHF Virus,Infection
What is a viral hemorrhagic fever?
A viral hemorrhagic fever is a viral disease, which has a tendency to disrupt
the clotting of the blood, so that patients may develop uncontrolled bleeding.
Usually fever, body aches, and other flu-like symptoms also are seen.
Many common diseases can resemble viral hemorrhagic fever, but the term is
reserved for a particular group of diseases associated with a high death
(fatality) rate.
In addition to CCHF they include Lassa fever, Rift Valley
fever, Alkhumra, Omsk hemorrhagic fever, Kyasanur forest disease,
Argentine, Bolivian, Brazilian, and Venezuelan hemorrhagic fevers (caused
by Junin, Machupo, Sabia, and Guanarito viruses, respectively), and
Marburg and Ebola hemorrhagic fevers.
The National Institute of Virology (NIV) 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 geographic range of CCHF virus is the most extensive among the tickborne viruses that affect human health, and the second most widespread of all medically important arboviruses, after dengue viruses
CCHF has become one of the most geographically widely distributed tick-borne diseases in the world; the disease, or the presence of the virus, has been reported from at least 31 countries in Africa, Asia, southeast Europe, and the Middle East.
Where does the CCHF virus come from?
A: The virus is transmitted mainly by Hyalomma ticks, adults of which have dis-
tinctive brown and white bands on their legs.
The virus can remain in the ticks for long periods, and even pass through the eggs to infect the next generation of ticks.
Immature Hyalomma ticks (larvae and nymphs) feed on ground-frequenting
(or ground-feeding) birds (guinea fowl, partridges, rooks) and small mammals
up to the size of hares.
Adult Hyalomma ticks feed on livestock such as cattle,sheep, and goats, as well as on wild animals such as antelope, wild boar, and ostriches.
Animals bitten by infected ticks do not develop the disease, but can circulate
the virus in their blood for a few days, up to 1 week, and thereafter become
immune to further infection.
Non infected ticks become infected if they feed on the animals during the short period when virus is in circulation, thus ensuring that the virus is perpetuated.
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.
The mortality rate from CCHF is approximately 30%, with death occurring in the second week of illness.
In those patients who recover, improvement generally begins on the ninth or tenth day after the onset of illness.
Crimean-Congo haemorrhagic fever (CCHF) is a viral haemorrhagic fever of the Nairovirus group.
The disease was first described in the Crimea in 1944 and given the name Crimean haemorrhagic fever.
In 1969 it was recognized that the pathogen causing Crimean haemorrhagic fever was the same as that responsible for an illness identified in 1956 in the Congo and linkage of the 2 place names resulted in the current name for the disease and the virus. CCHF is a severe disease in humans, with a high mortality rate.
The virus which causes CCHF is a Nairovirus, a group of related viruses forming one of the five genera in the Bunyaviridae family of viruses.
All of the 32 members of the Nairovirus genus are transmitted by argasid or ixodid ticks, but only three have been implicated as causes of human disease:
During the summers of 1944 and 1945 over 200 cases of an acute, hemorrhagic, febrile illness occurred in Soviet troops rescuing the harvest following the ethnic cleansing of the Crimean Tatars.
Soviet scientists first identified the disease they called Crimean hemorrhagic fever in 1944 and established its viral etiology by passage of the virus through human "volunteers"
CCHF or Congo reservoirs and vectors –
A reservoir is a place or a zone where a supply is kept in store.
Reservoir refers to a carrier of a virus or parasite for which they are not pathogenic.
Pathogenic means Capable of causing disease or Originating or producing disease.
Vector means any agent (person or animal or microorganism) that carries and transmits a disease; "mosquitos are vectors of malaria and yellow fever"
1.
The CCHF virus may infect a wide range of domestic and wild animals. Many birds are resistant to infection, but ostriches are susceptible and may show a high prevalence of infection in endemic areas. Animals become infected with CCHF from the bite of infected ticks.
2.
A number of tick genera are capable of becoming infected with CCHF virus, but the most efficient and common vectors for CCHF appear to be members of the Hyalomma genus.
3.
The most important source for acquisition of the virus by ticks is believed to be infected small vertebrates on which immature Hyalomma ticks feed.
Once infected, the tick remains infected through its developmental stages, and the mature tick may transmit the infection to large vertebrates, such as livestock. Domestic ruminant animals, such as cattle, sheep and goats, are viraemic (virus circulating in the bloodstream) for around one week after becoming infected.
How the Humans get infected by Congo or CCHF virus?
Humans who become infected with CCHF acquire the virus from direct contact with blood or other infected tissues from livestock during this time, or they may become infected from a tick bite.
The majority of cases have occurred in those involved with the livestock industry, such as agricultural workers, slaughterhouse workers and veterinarians.
The virus is transmitted to humans by the bite of Ixodid tick (mostly of the Hyalomma genus) or by contact with blood or tissues from human patients or infected livestock
The length of the incubation period for the illness appears to depend on the mode of acquisition of the virus.
Following infection via tick bite, the incubation period is usually one to three days, with a maximum of nine days.
The incubation period following contact with infected blood or tissues is usually five to six days, with a documented maximum of 13 days.
What are symptoms of Congo once it is acquired by Human?
Onset of symptoms is sudden, with fever, myalgia (aching muscles), dizziness, neck pain and stiffness, backache, headache, sore eyes and photophobia (sensitivity to light).
There may be nausea, vomiting and sore throat early on, which may be accompanied by diarrhoea and generalized abdominal pain.
Over the next few days, the patient may experience sharp mood swings, and may become confused and aggressive.
After two to four days, the agitation may be replaced by sleepiness, depression and lassitude, and the abdominal pain may localize to the right upper quadrant, with detectable hepatomegaly (liver enlargement).
Other clinical signs which emerge include tachycardia (fast heart rate), lymphadenopathy (enlarged lymph nodes), and a petechial rash (a rash caused by bleeding into the skin), both on internal mucosal surfaces, such as in the mouth and throat, and on the skin.
The petechiae may give way to ecchymoses (like a petechial rash, but covering larger areas) and other haemorrhagic phenomena such as melaena (bleeding from the upper bowel, passed as altered blood in the faeces), haematuria (blood in the urine), epistaxis (nosebleeds) and bleeding from the gums.
There is usually evidence of hepatitis. The severely ill may develop hepatorenal (i.e., liver and kidney) and pulmonary failure after the fifth day of illness.
What is the procedure to Diagnosis of CCHF or Congo Virus?
Diagnosis of suspected CCHF is performed in specially-equipped, high biosafety level laboratories. IgG and IgM antibodies may be detected in serum by enzyme-linked immunoassay (the "ELISA" or "EIA" methods) from about day six of illness. IgM remains detectable for up to four months, and IgG levels decline but remain detectable for up to five years.
Patients with fatal disease do not usually develop a measurable antibody response and in these individuals, as well as in patients in the first few days of illness, diagnosis is achieved by virus detection in blood or tissue samples.
There are several methods for doing this.
The virus may be isolated from blood or tissue specimens in the first five days of illness, and grown in cell culture.
Viral antigens may sometimes be shown in tissue samples using immunofluorescence or EIA.
More recently, the polymerase chain reaction (PCR), a molecular method for detecting the viral genome, has been successfully applied in diagnosis.
Treatment for Congo or CCHF –
General supportive therapy is the mainstay of patient management in CCHF. Intensive monitoring to guide volume and blood component replacement is required.
The antiviral drug ribavirin has been used in treatment of established CCHF infection with apparent benefit.
Both oral and intravenous formulations seem to be effective.
The value of immune plasma from recovered patients for therapeutic purposes has not been demonstrated, although it has been employed on several occasions.
Ribavirin aerosol is antiviral drug that could be also used in viral hemorrhagic fever syndromes. Besides Crimean-Congo hemorrhagic fever (CCHF), it is used in Lassa fever
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