TB Experts: FT influx from 3rd world increases reported cases in Singapore

By: Forever Vagabond
It was reported that 6 drug-resistant TB cases were recently discovered coming from the same HDB block in Ang Mo Kio Ave 3 (https://theindependent.sg.sg/cluster-of-multi-drug-resistant-tb-cases-discovered-in-a-single-block-in-ang-mo-kio).
The cluster was detected by a vigilant doctor from the Tuberculosis Control Unit at Tan Tock Seng Hospital. The 6 were infected with the same drug-resistant (MDRTB) strain, with the last case confirmed on 10 June.
The route of transmission for the unrelated individuals not living in the same unit has yet to be determined. MOH is now offering free TB screening as a precautionary measure to the residents of Block 203 Ang Mo Kio Ave 3.
Increase in TB cases in Singapore
It’s not known how the 6 persons in Ang Mo Kio were infected but certainly, concerns of the rapid increase of population in Singapore in the last number of years, contributing to the increase of TB cases in Singapore have been surfacing online for many years.
Even MOH reported that TB rates were falling till 2007 before making a u-turn. From 1987 to 1998, the rate of TB among residents was ranging from 49 – 57 per 100,000 resident population. By 2007, the rate has declined to a low of 35 per 100,000.
“In recent years, we have seen a resurgence of TB in Singapore,” acknowledged MOH (https://www.moh.gov.sg/content/moh_web/home/diseases_and_conditions/t/tuberculosis.html).
MOH reported 1,498 new TB cases among Singapore residents (citizens and PRs) in 2015, which is higher than the 1,454 cases in 2014. Correspondingly, the incidence rate was 38.4 cases per 100,000 in 2015, increasing from 37.4 in 2014.
The number of non-residents (foreigners on long term stay here for work, study or visit) notified with TB was 1,206 in 2015 compared to 1,287 in 2014 (https://www.moh.gov.sg/content/moh_web/home/pressRoom/pressRoomItemRelease/2016/-moh-launches-clinical-practice-guidelines-in-fight-against-tube.html).
So, in 2015, out of a total of 2,704 reported TB cases, non-resident foreigners contributed 45% of the cases, even though they only constituted 29.5% of the population (1.6 out of 5.5 million) (http://population.sg/population-in-brief/files/population-in-brief-2015.pdf).
TB experts concerned about increase of TB cases among foreign-born population in Singapore
Several years ago, TB experts have already noticed the increase in proportion of foreign-born persons with TB in Singapore (http://wwwnc.cdc.gov/eid/article/17/3/10-1615_article).
The authors of the paper noted the increase in proportion of foreign-born persons with TB in Singapore. They wrote, “Unskilled workers from countries with high incidences of TB accounted for the highest number of and greatest increase in foreign-born TB case-patients.”
They noted that after the economic recovery and liberalization of the immigration policy in Singapore in 2005, there was an influx of migrant workers and immigrants from countries with high incidences of TB and a corresponding increase in TB notifications among this population.
“Of these persons with TB, >75% came from 5 of the 7 countries (India, China, Indonesia, Bangladesh, and the Philippines) with highest incidences of TB,” the authors reported.
They also said that TB transmission from foreign-born to native-born persons may have occurred, especially in increasingly crowded urban settings of Singapore. “However, this proposal cannot be verified without DNA fingerprinting studies,” they added.
In another paper to the Annals Academy of Medicine (http://www.annals.edu.sg/pdf/39VolNo3Mar2010/V39N3p261.pdf), the authors added, “There is a significant risk of TB arising from foreigners who come to Singapore to reside for work or study. Many of the source countries e.g. China, India, Indonesia, Philippines, Myanmar and Vietnam, have high incident rates of TB, and also not insignificant MDR-TB (drug-resistant TB).”
“A review of MDR-TB (drug-resistant) cases in Singapore from 2000 to 2006 reported 48 non-resident MDR-TB cases. The majority of the cases were from Indonesia (52%), Myanmar (17%) and China (10%),” said the paper.
“Doctors therefore need to recognise that a foreigner with chronic cough may not only have TB, but also MDR-TB (drug-resistant TB). A number of patients from the region also come to Singapore to seek treatment after failed TB treatment in their home countries. These patients may also have MDR-TB.”