Crimean-Congo haemorrhagic fever, symptoms and control

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Introduction


Now-a- days many of cases of Crimean-Congo haemorrhagic fever (CCHF) are being reported in


different cities of Pakistan. Crimean-Congo haemorrhagic fever (CCHF) is primarily an animal


disease; however, sporadic cases and outbreaks of CCHF have also been reported in humans.


Crimean-Congo hemorrhagic fever is caused by Crimean-Congo hemorrhagic fever virus


(CCHFV). This virus is a member of the genus Nairovirus in the family Bunyaviridae. It belongs


to the CCHF serogroup. Although early serological studies revealed very few differences


between strains of CCHFV; however, nucleic acid sequence analysis has demonstrated extensive


genetic diversity, particularly between viruses of different geographic regions.


The virus was first isolated in Pakistan (Changa-Manga forest), in 1960s from ticks while the


first case was reported in Pakistan in 1976 in Rawalpindi when a physician treating a patient with


abdominal pain, melena and hematemesis at the Central General Hospital now named Benazir


Bhutto Hospital. In addition, an operation theatres attendant also died while attending that


patient. Another outbreak was stated in December 1994 in Baluchistan (Quetta) which resulted in


death of the patient. Two surgeons who were operating on him also found infected with the virus


along with a health care personnel at Agha Khan University Hospital, Karachi, where these


surgeons were being treated.


On the evening of 7th December 2005, a 32 years old previously healthy man was admitted to


the Combined Military Hospital, Abbottabad. He belonged to a family which owned butchery


and barbeque shop. Within 24 hrs of hospital admission he died because of multi-organ failure.


His blood PCR was positive for CCHF virus. According to National Institute of Health (NIH)


report, in2015, at least 25 CCHFV positive patients in critical condition from Peshawar, Dir,


Kohat and Swabi were brought to Hayatabad Medical Complex and out of them, 11 died. The


most notable point in different outbreak cases remained its transmission.


Transmission


The virus is transmitted to humans through the bite of an infective adult tick of the genus


Hyalomma, and even crushing an infected tick also causes infection by skin lesions. It was


observed that besides person to person transmission; there are some additional factors, including:


infected blood and tissues of animals, bloody vomit and body fluids of humans. The injections


and surgical procedures in hospitals may also play a vital role in spreading the disease.


Therefore, those professions which deal with infected animals and humans such as livestock


breeders, abattoir workers and healthcare workers are at high risk to this disease. Mass scale


animal movements anticipated prior to Eid-ul- Azha could serve as a source of propagation for


ticks infested with CCHF virus thereby increasing the risk of disease transmission, which require


possible control measures.


Incubation Period


The incubation period is influenced by the route of exposure. Infections acquired via tick bites


usually become apparent after 1 to 3 days; the longest incubation period reported by this route is


nine days.


Clinical Signs


The first sign of Crimean-Congo hemorrhagic fever is a sudden onset of fever and other


nonspecific symptoms including chills, severe headache, dizziness, photophobia, neck pain,


myalgia and arthralgia. The fever may be very high. Gastrointestinal symptoms including


nausea, vomiting, non-bloody diarrhea and abdominal pain are also common. Sharp mood


changes, confusion and aggression have been reported in some cases. Cardiovascular changes


such as bradycardia and low blood pressure can also occur. This early stage of disease is called


the pre-hemorrhagic phase. It is followed, after several days, by the hemorrhagic phase. Other


symptoms including sweating, dryness of the mouth, headache, dizziness, nausea, poor appetite,


labored breathing, polyneuritis, poor vision, loss of hearing, and memory loss have also be seen.


Some patients temporarily lose all of their hair. Hepatorenal insufficiency has also been reported


in some countries.. Recovery is usually complete but slow, and can take up to a year.


Diagnostic Tests


CCHF can be diagnosed by isolating virus from blood, plasma or tissues. The virus is most


likely to be found in the lung, liver, spleen, bone marrow, kidney and brain. CCHFV can be


isolated in a variety of cell lines including SW-13, Vero, LLC-MK2 and BHK-21 cells. Cell


cultures can only detect high concentrations of the virus, and this technique is most useful during


the first five days of illness. CCHFV is identified by indirect immune fluorescence or reverse


transcription-polymerase chain reaction (RT-PCR) assays. Virus isolation must be carried out in


maximum bio-containment laboratories (BSL-4).


Treatment and control


Treatment is mainly supportive, however: Ribavirin is a drug that is used in some cases.


Observational studies in humans and studies in experimentally infected mice support the use of


this drug; however, no randomized human clinical trials have been published. Several drugs


including: Negawan ,Separmethrin, Deltabak and Ivermectin are also being used to control ticks.


As, this is an emerging disease and transmit through a vector, therefore, it requires a considerable


notice at government and public health departments e.g. proper insecticidal spray on animals and


premises, routine hematological screening of animals and their owners, use of gloves and mask


while purchasing and sale of animals. By proper hygienic and control measures, especially in


meat markets and where animals are brought to sale (Bakra Mandi), it is possible to manage its


spreading.


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Published in: Volume 07 Issue 30

Short Link: http://www.technologytimes.pk/?p=15995