Sri Lanka Coronavirus contact tracing gaps plugged as incubation of SARS-Cov-2 suspected to top 20 days
ECONOMYNEXT – Sri Lanka is quarantining all close contacts (F1) of the confirmed Coronavirus (index case or F0) and will test all quarantined persons before release amid mounting evidence that incubation of SARS-Cov-2 virus incubation may take up to 20 days or more in a minority of cases.
A Sri Lankan returnee from Italy who completed 14 days of quarantine was seen later found to have been infected with Covid-19 on April 06, around 20 days after the person arrived in the country.
Tests in Quarantine
“We will test all persons who are placed in quarantine,” the head of Sri Lanka’s Health Service Anil Jasinghe said.
“The person will be tested 7 days after quarantine and at 13 days”
Sri Lanka is also ramping up tests to screen at least 3,000 close contacts of confirmed cases, he said.
Sri Lanka has confirmed 189 cases and 44 have recovered and 7 persons have died by April 08.
Sri Lankan authorities are confident that based on procedures followed in the country, the Italian returnees could not have got infected inside the quarantine centre.
Sri Lanka has urged all released quarantine persons to self quarantine for another 14 days just in case the incubation was longer than advised by the World Health Organization.
“It is very important that 14 days home quarantine be followed,” Sri Lanka’s Army Chief Shavendra Silva said on April 06.
“This person seems to have developed the disease about 7 to 8 days after release.”
Reliable information on Covid-19 is still not available as initial information came from China, where authorities found the disease only as serious pneumonia cases turned up and as the disease spread like wildfire public services collapsed and bodies piled up at crematoria a few weeks later.
Only a few countries such as Korea, Vietnam and Sri Lanka where contact tracing has been unleashed and arrivals from China restricted or quarantined early, are health services and other authorities able to track infected persons with any degree of accuracy.
In Vietnam patient 243, a male who visited hospital in Hanoi which was exposed to Covid-19 was found with the disease about 23 days later.
Sri Lanka is now placing all close contacts of index cases to quarantine General Silva said.
On April 05, 144 close contacts of a case in Akurana has been taken to quarantine. Akurana area itself is on lockdown and the Kandy district is on indefinite curfew as a high risk area.
Forty four close contacts of a confirmed person found in Pannipitiya had been taken to quarantine this week he said.
Fifty five close associates of an index case in Mt. Lavinia found in Ratmalana and Orugodawatte was taken to the Punani centre.
Sri Lanka is under curfew to find infected persons, who may have slipped through the contact tracing net, and may develop the disease or trigger their own cluster.
Sri Lanka’s curfew is not the same as lockdowns seen in Western nations such the US, UK or Wuhan where community transmission is already out of controls, many are dying and the separation is simply a mitigation strategy.
Authorities are hoping to ease restrictions after April 17, if no large clusters develop from any persons that have slipped through the contact tracing net.
However concerns are raised that some person with a longer incubation periods may be running loose. Sri Lanka’s police have extended curfew passes issued to so-called essential services until the end of the month.
Researchers in Vietnam where contact tracing was advanced early are testing all F1 contacts of an index case immediately. If any F1 contacts are confirmed F2 (the contacts of F1) are also tested and F3 traced in paper to be published in the the International Journal of Tuberculosis and Lung Disease (IJTLD).
The authors from the Woolcock Institute of Medical Research, Hanoi, Viet Nam; Sydney School of Medicine, Faculty of Medicine and Health, The University of Sydney, Australia, supported by others in Laos say at least three generations of contacts of an index has have to be traced and two tested to successfully kill community transmission.
All asymptomatic persons should be quarantined, the researchers said.
Authors T A Nguyen, Q N Cuong, A L T Kim, T N Huong, H N Nguyen, G J Fox, G B Marks, say once a patient had been identified (F0), the next generation should be tested and another two generations traced.
“First, three generations of contact (F) with COVID-19 cases should be traced to offer timely testing if the previous contact generation is found positive,” they wrote.
“This algorithm starts with the first generation (F1) who are close contacts of the index case (F0).
“All F1 contacts should be tested for SARS-CoV-2 regardless of symptom presentation.
“F1 individuals who are asymptomatic or have two negative tests 24 hours apart should be quarantined for 14 days.”
Vietnam is also doing wider testing of suspected high risk areas. Up to April 09 Vietnam has done 109,000 tests.
There have been no deaths, but five person are in serious condition, including a Vietnamese airlines pilot who is a British national who has been placed on a external blood oxygenation machine.
Against the trend
Sri Lanka, Korea and Vietnam are among countries that are aggressively hunting Wave II infections after successfully containing Wave I from China.
Sri Lanka and Vietnam are among countries that controlled arrivals from China or quarantined ‘healthy’ travellers against the advice from the World Health Organization at the time.
Vietnam has engaged in surgical lockdowns and kept the economy ticking, though inter-provincial travel is being tightened.
Vietnam also quarantined ‘healthy’ arrivals from China going against WHO general advice from early on and extended it to other foreigners and Vietnamese citizens during Wave II.
Most of the worst respiratory viral pandemics in the last century have come from China.
The Asian Flu of 1957 to 1958 which is estimated to have killed between 1 to 4 million people worldwide according to UK’s Health Department data, originated in Southern China.
The Hong Kong flu of 1968 to 1969 also from Southern China is estimated to have killed between 1 – 4 million people and 80,000 in the UK.
The 2009-2020 Swine Flu from Mexico is believed to have killed over 18,000 people worldwide.
The Spanish flu of 1918-1919 is estimated to have killed up to 50 million people worldwide.(Colombo/Apr09/2020)