Crimean-Congo haemorrhagic fever, symptoms and control
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.
