Post-monsoon climate conditions conducive now for dengue, chikungunya, zika viruses outbreaks
M. Waqar Bhatti:
Islamabad: Pakistan is facing a potential outbreak of mosquito-borne viral diseases as the retreat of the monsoon has created ideal conditions for the spread of dengue, chikungunya, and Zika viruses, the Pakistan Meteorological Department (PMD) warned.
According to a PMD ‘Dengue Alert’ issued today, climatic conditions in late September, particularly in urban centers, have become highly conducive for these viruses to thrive.
With dengue cases already surging across the country, especially in Khyber Pakhtunkhwa, Punjab, and Islamabad, public health experts are raising alarms over chikungunya and the recently confirmed circulation of the Zika virus in Karachi.
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Dengue fever has steadily entrenched itself as a major health threat in Pakistan over the past decade, typically spiking during the post-monsoon season. Favorable environmental factors, such as temperatures between 26-29°C and humidity levels above 60%, create an ideal breeding ground for the Aedes aegypti mosquito, the primary carrier of dengue, chikungunya, and Zika.
PMD data analysis indicates that these conditions are expected to persist from mid-September to early December, with October being a high-risk period for viral outbreaks in major cities, including Karachi, Lahore, Islamabad, Rawalpindi, and Peshawar.
The Aedes mosquito, which is most active two hours after sunrise and two hours before sunset, breeds in stagnant water left behind by monsoon rains.
The PMD maintains that current rainfall levels exceeding 27mm, combined with temperature and humidity patterns, present an almost perfect environment for mosquito proliferation. The situation is expected to worsen if temperatures do not drop below 16°C, which would otherwise halt mosquito breeding.
Health officials are concerned that dengue may not be the only virus spreading during this time. The National Institute of Health (NIH) has reported a weekly rise of over 2,000 dengue cases across the country, alongside 250 cases of chikungunya, a virus that causes fever, joint pain, and rashes. Both viruses are transmitted by the same species of mosquito.
An NIH official warned that actual chikungunya cases could be up to ten times higher than reported, as most are diagnosed clinically without PCR testing. Provinces such as Punjab and Khyber Pakhtunkhwa (KP) have been particularly affected, with significant case spikes in cities like Rawalpindi and Peshawar.
The official further claimed that many provincial governments are underreporting the true extent of the outbreaks. For instance, in just one day, Islamabad’s Polyclinic sent over 150 samples for dengue testing. Yet, provincial reports did not match these alarming figures, the official said.
He noted that over 2,000 dengue cases and over 250 chikungunya cases are being reported weekly across Pakistan, with underreporting especially common in KP and Sindh.
The detection of the Zika virus in Karachi has also raised concerns. Zika, which shares the same mosquito vector as dengue and chikungunya, is particularly dangerous for pregnant women, as it can cause severe birth defects like microcephaly.
While Zika cases in Pakistan remain limited, its presence in densely populated Karachi has fueled fears of a broader outbreak. Public health officials are urging immediate action to prevent the spread of Zika nationwide, warning that the virus could soon become a nationwide health emergency if left unchecked.
In response to these threats, provincial health departments have issued advisories, urging the public to take preventive measures. The Punjab Health Department reported a significant spike in dengue cases this week, with 126 new infections recorded in the last 24 hours, bringing the total to 528 for the week and 1,371 cases for the year. Rawalpindi remains the hardest-hit city, accounting for 107 of the new cases, while Lahore, Gujranwala, and other cities reported fewer, but still concerning, numbers.
Health officials are emphasizing the importance of maintaining clean surroundings and eliminating standing water, which serves as breeding grounds for mosquitoes. Citizens are urged to cooperate with health teams conducting fumigation and larvicidal activities.
The next two months, according to the NIH, are critical for controlling the spread of these viruses. The NIH has also set up a free helpline (1033) to provide information, advice, and a channel for reporting unsanitary conditions that could contribute to outbreaks.
The stakes are particularly high for Pakistan’s already strained healthcare system. Hospitals, especially in Punjab, have been placed on high alert, and the government has assured the public that medical supplies, including treatments for dengue and chikungunya, are in stock. However, with the possibility of simultaneous outbreaks of dengue, chikungunya, and Zika, the healthcare system may face significant challenges in coping with the rising number of cases.
As October approaches, Pakistan’s battle against mosquito-borne viruses intensifies. The PMD’s warning, combined with rising case numbers and the presence of Zika in the country, underscores the need for a coordinated national response. The coming months will be crucial in determining whether Pakistan can prevent a widespread health crisis fueled by a perfect storm of climatic and environmental factors.
