Zika virus in Karachi
Overview of Zika virus in Pakistan
The Zika outbreak, primarily transmitted by Aedes mosquitoes, has emerged as a significant public health concern due to its potential to cause severe birth defects and neurological complications. Although the virus has been known since the mid-20th century, its presence in Pakistan was only confirmed recently.
Discovery in Karachi
In 2021, researchers from the Aga Khan University (AKU) in Karachi, collaborating with the United World Antiviral Research Network (UWARN), identified the Zika epidemic during an outbreak of a mysterious viral illness. Initially, patients presented with symptoms similar to dengue fever, such as reduced platelet and white blood cell counts, but tested negative for dengue. Following an in-depth investigation, two cases of the virus were detected and later confirmed through metagenomics at the Gale Lab at the University of Washington, Seattle. These findings marked the first confirmed presence of the ZIKV in Pakistan.
Transmission
The ZIKV is predominantly spread by infected mosquitoes from the Aedes genus, particularly Aedes aegypti, which are prevalent in tropical and subtropical areas. These mosquitoes are daytime biters and are also responsible for transmitting other diseases such as dengue, chikungunya, and urban yellow fever.
In addition to mosquito bites, ZIKV can be transmitted from an infected mother to her fetus during pregnancy. It can also spread through sexual contact, blood transfusions, and potentially through organ transplantation.
Symptoms
Most individuals infected with the ZIKV do not exhibit symptoms. However, those who do may experience:
- Rash
- Fever
- Conjunctivitis (red eyes)
- Muscle and joint pain
- Malaise
- Headache
These symptoms generally last for 2-7 days.
Complications
- During Pregnancy: This infection can lead to severe congenital malformations, including microcephaly (a condition where a baby is born with a significantly smaller head) and other birth defects. It can also result in preterm birth and miscarriage.
- Neurological Disorders: The virus is linked to Guillain-Barré syndrome, neuropathy, and myelitis in both adults and children.
Treatment
There is no specific antiviral treatment for Zika virus infection. Management primarily involves symptomatic relief:
- Rest
- Hydration
- Use of antipyretics and analgesics (avoiding NSAIDs until dengue is ruled out due to bleeding risks)
Precautions
- Mosquito Control:
- Use insect repellents containing DEET, IR3535, or icaridin.
- Wear long-sleeved clothing and use physical barriers like window screens.
- Sleep under mosquito nets, especially during the day and early evening when Aedes mosquitoes are most active.
- Eliminate standing water where mosquitoes breed, such as in flowerpots and discarded tires.
- Sexual Transmission:
- Practice safe sex or abstain from sexual activity, particularly in areas with active Zika transmission.
- Pregnant women should take extra precautions to avoid infection.
Response and Surveillance
Despite the confirmation of Zika virus in Karachi, there remains a lack of formal reporting and awareness among public health officials. The Sindh Health Department continues to report cases of dengue, chikungunya, and other vector-borne illnesses, but Zika virus cases have not been widely acknowledged.
Conclusion
The identification of the Zika virus in Karachi underscores the importance of ongoing surveillance and research into emerging viral threats. Public health authorities must enhance efforts to educate healthcare providers and the public about Zika virus, its symptoms, complications, and preventive measures to mitigate its impact on the population.
