With the government in denial over surfacing of new dengue cases, medical experts have challenged the efficacy of NS1 tests to detect dengue virus among patients, Pakistan Today has learnt.
Per details, Chief Minister Shahbaz Sharif’s special Advisory Board on Dengue working under Professor Dr Faisal Masood and other experts issued new guidelines to confirm dengue virus among patients. These new guidelines have recommended a non-structural glycoprotein (NS1) test to diagnose dengue instead of the usual immunoglobulin G (IGG) and immunoglobulin M (IGM) tests that have been in use till now to detect dengue.
However, medical experts have termed just the NS1 test “inadequate” on various ground saying the IGM and IGG tests are “essential” to know about “the actual infected population”.
A senior expert said, “Life of dengue virus in a body is about 5 to 7 days in most cases after which natural antibodies IGM and IGG appear in the infected individual…we can only detect the NS1 antigen when the virus is present in the blood of the infected person…After 5 to 7 days the person may be a dengue patient but they will be negative for NS1 because of the development of IGM and IGG respectively.”
Moreover, per the Pan-American Health Organisation Guidelines, IGM antibody is detectable by day five of illness in 80 percent of all dengue cases and by day six to 10 in around 93 to 99 percent of the cases which remain detectable for up to 90 days. They further said NS1 should only be performed as an early “epidemic marker” while other antibodies such as IGM and IGG should also be considered for further surveillance of disease. “It is impossible to know about the actual infected population without the help of IGM and IGG in a country with limited resources like Pakistan,” the expert added. Another senior doctor seeking anonymity said the entire “traditional literature” suggests that IGM and IGG should be done to detect dengue, but the new guidelines have been issued by senior professor appointed by the CM and hence all doctors are “duty-bound” to follow these guidelines.
PUNJAB GOVERNMENT DENIES: Earlier, denying the surfacing of new cases, Special Assistant to Punjab Chief Minister on Health Khwaja Salman Rafique has said that no confirmed dengue patient has been reported and the test was coming out to be positive on last year’s patients. He said the CM was personally supervising the arrangements regarding dengue and health and other departments were on high alert. He said that dependency units have already been established in the hospitals and work on dengue mosquito and vector surveillance was being carried out efficiently.
This was stated by him during a press conference accompanied by Chairman Dengue Expert Advisory Group Professor Faisal Masood and Allama Iqbal Medical College Principal Professor Javed Akram at DGPR on Monday. Director General Dr Nisar Cheema, Vector Borne Diseases Addl. Director General Dr Jaffar Ilyas and Mayo Hospital MS Dr Zahid Pervaiz were also present on the occasion. Prof Faisal Masood said 30 percent of Lahore’s population was infected by dengue last year. He said at present, typhoid and malaria cases were being reported in the patients suffering from fever whereas IGG and IGM tests of dengue were found positive in suspected patients. Therefore, the Dengue Advisory Group had recommended the NS-I test of suspected dengue patient to differentiate the old and new patients. Faisal Javed Akram said per experts of vector surveillance, there no vector of dengue mosquito was found anywhere so far, therefore, there was no possibility of any dengue patient. He said if a dengue patient was reported in the hospital, the media would definitely be informed about it.
In reply to a question, Rafique said at present, dengue mosquito was not found anywhere, therefore, there was no need of fogging and spray. He said that the experts are monitoring the situation effectively and if required, target spray and fogging will be carried out so that the people could be saved from the use of unnecessary chemicals. He said private hospitals and laboratories had extended cooperation to the government during dengue virus last year and expressed the hope that this time too they would also extend full cooperation to the government.
