health
Friday Mar 11 2022
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Is West Nile virus rearing its head in Pakistan?

Colourized transmission electron micrograph (TEM) of West Nile virus.-Courtesy Britanica
Colourized transmission electron micrograph (TEM) of West Nile virus.-Courtesy Britanica
  • Unexplained deaths of, including crows, kites and pigeons in Karachi, Islamabad and other cities indicate the presence of WNV.
  • The West Nile Virus is spread by a species of mosquitoes present in Pakistan and cause fever in humans.
  • Most people with WNV do not develop any symptoms but in some people, symptoms of severe illness could be high fever, headache.


KARACHI: Infectious diseases experts feared that the unexplained deaths of various species of birds, including crows, kites and pigeons in Karachi, Islamabad and other cities indicate the presence of West Nile Virus (WNV).

The West Nile Virus spread by a species of mosquitoes present in Pakistan and cause fever in humans, according to a report published in The News on Friday.

They said although no test is available at the moment at most of the clinical laboratories in Pakistan to detect West Nile Virus, clinical symptoms in some of the patients also confirm that people are getting infected with the vector-borne disease, which can prove to be lethal for people of old ages and those having weak immune systems.

WNV can cause death in humans

According to World Health Organisation (WHO), West Nile Virus (WNV) can cause neurological disease and death in people. It is commonly found in Africa, Europe, the Middle East, North America and West Asia. The virus can cause a fatal neurological disease in humans; however, approximately 80% of people who are infected will not show any symptoms.

“Deaths of birds especially crows, across the country is possibly West Nile Virus given the reason. Have seen (such cases), every year. Expecting human cases as well; though may not be picked up as most physicians are unable to recognise this disease,” said Dr Faisal Mehmood, infectious diseases expert at Aga Khan University Hospital (AKUH) Karachi while talking to The News

Commenting on the unexplained deaths of crows in different cities of Pakistan, Dr Faisal said when such a large number of crows and other birds start dying, it is most probably due to the West Nile Virus infection, which is caused by a species of mosquitoes known as Culex, which are very common in Pakistan. 

"When they bite humans, they infect the people with West Nile Virus causing West Nile fever," he said.

He informed that a study conducted by Dr Erum Khan of AKU had found 105 people positive for WNV IgM antibodies, and 71 of these patients possessed WNV-specific neutralising antibodies in 2016 and added that in clinical practice too, they are observing cases of West Nile Virus infection with its classical symptoms.

Symptoms

“Most people with West Nile Virus infection do not develop any symptoms but in some people, symptoms of severe illness could be high fever, headache, neck stiffness, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis,” he said, adding that severe illness can occur in people of any age; however, people over 60 years of age are at greater risk for severe illness if they are infected. 

To a query, he said the study conducted by the AKU researcher had found the suspected cases of West Nile Viral infection in the fall, in the months of September, October and November but now the suspected cases of West Nile Fever are emerging in the months of February and March, which is a little unusual.

Dr Faisal Mahmood maintained that some neurologists have also reported symptoms of the virus in some patients and they have been requested to forward such cases to AKU for confirmation, but added that most of the time cases of this viral infection can be missed by the general physicians and even neurologists.

Most labs don’t have facility to detect WNV

When asked how they could detect the West Nile Virus in Pakistan, he informed that although most of the clinical labs don’t have the facility to detect the WNV, the research lab at AKU had the facility to detect this virus as well as other viruses that caused Arboviral diseases including dengue, malaria, chikungunya and Zika virus disease.

“At the moment, there is no need to get scared of this disease or the virus and people should adopt the same precautionary measures, which they take to prevent themselves from dengue or malaria,” he said and added that mosquitoes have become a serious public health concern in Pakistan. 

Another infectious diseases expert at Indus Hospital Karachi, Dr Naseem Salahuddin said they were actively discussing it (presence of West Nile Virus in Pakistan) amongst infectious disease clinicians and microbiologists, but have not arrived at any conclusion yet.

“There are no definite tests available. Dr Erum Khan at AKUH who has conducted tests in the past and other experts at the AKUH know better in this connection,” Dr Salahuddin added. 

Responding to the queries, Director General Health Pakistan Dr Rana Muhammad Safdar said they had received some ‘off the record’ reports of this viral disease in the country but so far no ‘on the record’ and credible report of this disease has been received yet.

Dr Safdar, who is himself an expert of Emerging Infectious Diseases, said they have asked the National Institute of Health (NIH) Islamabad to look into this matter and start surveillance of suspected cases and get the samples to confirm whether WNV is circulating in the community or not.