.
By the end of
2016, the Zika epidemic in the Americas was reducing, but Yale epidemiologist
and lead author Nathan Grubaugh, and other members of the study team wanted to
explore the possibility whether hidden outbreaks and transmission of infection
might still be occurring and were going undetected with risk of serious
epidemics if these outbreaks were not identified on time and preventive
measures put in place.
"Accurate case detection is not always possible in many places for a variety of
biological and socioeconomic reasons," said Grubaugh.
"So, we constructed a framework using
infections diagnosed from travelers, travel patterns, and virus genomics to
detect outbreaks in the absence of local data." Identifying
Unreported 2017 Zika Outbreak in Cuba
- More than 98 percent of the travel-related cases
reported in Europe and Florida between June 2017 and October 2018 was
coming from Cuba
- According to the study team's estimates around
1000-20,000 Zika cases should have occurred in Cuba in 2017, although
not a single case was reported
- Scientists were puzzled by the timing of the
Cuban outbreak i.e., in 2017, much later than the American Zika
outbreak which was actually beginning to reduce by the end of 2016
- The research team found that the delay was probably due to a successful mosquito
eradication campaign launched in Cuba in 2016
- The mosquito control efforts of 2016 were initially
effective but then waned sparking the 2017 Zika outbreak by long-lasting
forms of the virus from 2016
Grubaugh said,
"Our data suggest that while
mosquito control in Cuba may initially have been effective at mitigating Zika
virus transmission, such measures may need to be maintained to be
effective." Challenges of Detecting Zika Outbreaks
- Symptoms of Zika similar to other infections such
as fever, headache, muscle and joint pains,
rash
etc.
- Low and middle-income nations may not have adequate
health care systems or surveillance methods
- Using unreliable and inexpensive diagnostic tools
Unless Zika
outbreaks are detected early with the availability of adequate health care resources and reliable
equipment, there is a danger of these outbreaks spinning out of control into
huge epidemics and pandemics.
Scope of the Study
- Zika virus transmission is still a major health
challenge in countries like India, Thailand and Angola. Using methods
similar to those used in this study, it may be possible to identify hidden
outbreaks in other parts of the world and put safety measures in place
- The analytical methods developed by the research
team can also be applied in order to detect hidden outbreaks of other
infections that go undetected due to challenges faced by local systems
In summary,
analyzing travel patterns and reports of infections in travelers combined with
viral gene analysis, it is possible to detect outbreaks of Zika as well as
similar infections before it spirals out of control.
Reference :- Scientists Detect Hidden Zika Outbreak In 2017 Using Travel Patterns & Viral Genetics - (http://dx.doi.org/10.1016/j.cell.2019.07.018)
Source: Medindia