Friday, September 24, 2021

Cuba relying on bacteria to end dengue epidemic

Dr. Maria Guadalupe Guzman, the research chief at Cuba’s Pedro Kouri Tropical Medicine Institute, speaks with EFE on Aug. 20, 2019, at the 16th International Conference on Dengue, Zika and Chikungunya in Havana. EFE

Havana, Aug 21 (EFE).– The dengue epidemic in several Latin American countries is also affecting – albeit to a lesser degree – Cuba, where experts are relying on containing the virus with new weapons: the Wolbachia bacterium and the sterilization of male mosquitoes.

“They are two tools that are being used in several countries on an experimental basis. If applied along with other measures and the participation of the community, they could help us much more than what we have in hand today to contain the (virus),” Guadalupe Guzman, the research chief at the Pedro Kouri Tropical Medicine Institute, told EFE.

Dr. Guzman is heading the 16th International Conference on dengue, Zika and other emerging arboviruses, which began on Aug. 12 and will run until the 23rd in Havana with experts from some 50 countries in attendance, including representatives of the World Health Organization (WHO) and Pan American Health Organization (PAHO).

Wolbachia is a bacterium that is found in 60 percent of mosquitoes that prevents the Aedes aegypti species of the insect from transmitting dengue, Zika and chikungunya.

However, Aedes aegypti does not acquire the bacterium naturally, and so researchers are introducing it into the insects in the laboratory using biotechnology. When the insects are released, they reproduce with wild mosquitoes and over time the percentage of the pests with Wolbachia in their systems rises until it remains high without the need for further releases of infected bugs.

“That’s what we’re banking on: having mosquitoes infected with Wolbachia that after breeding produce infected offspring, thus creating a population of mosquitoes that is resistant, that don’t transmit the virus when they bite you,” Guzman said.

Seven of every 10 people in the Americas is at risk of contracting dengue, a disease that this year has infected more than two million people in the region, according to WHO figures released at the conference.

Cuban epidemiologist Luis Valdes, who participated in the event, emphasized another important way that Cuba is plannint to implement to combat the disease: releasing huge numbers of sterile Aedes aegypti mosquitoes in areas where the epidemic is occurring.

“The latest thing, which other countries like Mexico and Brazil are doing, is releasing sterile mosquitoes so that they mate with females, who then don’t reproduce. The female bites because it needs to bring its eggs to maturity, but if it’s not fertilized it cannot transmit dengue (because) it doesn’t bite,” he said.

This technique only results in a temporary solution, since irradiating the male mosquitoes only temporarily sterilizes them, meaning that it is necessary to keep releasing batches of newly sterilized bugs to keep down the population.

Cuba is one of the countries in the Americas where the effects of dengue are less severe, and local authorities say that that there have only been 1,000 reported cases so far this year and no deaths.

However, estimates are that the true number of cases could be higher because many people who contract an arbovirus don’t go to the doctor or notify health authorities so as to avoid the 40-day quarantine that will be imposed on them.