In medicine, a disease is considered asymptomatic if a patient is a carrier for a disease or infection but experiences no symptoms. A condition might be asymptomatic if it fails to show the noticeable symptoms with which it is usually associated. Asymptomatic infections are also called subclinical infections. The term clinically silent is also used.
Along with asymptomatic malaria carriers, one symptomatic malaria case with symptom of mild fever was also detected.
Chief Entomologist of VDCP Rinzin Namgay said the surveillance was carried out ever since 10 September this year after the PHPA requested the VDCP team.
Till date six cases were detected by the two VDCP teams in PHPA I and PHPA II.
The blood screening of about 2500 project workers from both the projects including the shopkeepers and hoteliers residing around the place were done where not a single Bhutanese were detected.
It was diagnosed positive with help of Rapid Diagnostic Test (RDT) and malaria microscopy where the parasites were found present in the blood.
The Chief Entomologist said out of two types of malaria parasites in Bhutan, Plasmodium falciparum was seen in PHPA II with two cases and four cases of Plasmodium vivax from PHPA I.
He said there are more chances of spreading since they are not suffering adding “it is dangerous if they don’t go to hospital for treatment, they will remain as a reservoir and spread to others.”
The VDCP team found the presence of Anopheles mosquitoes through the surveillance. These mosquitoes bite infected patients; the carriers later transmit it to others.
It is said the five asymptomatic malaria carriers were normal and working as usual without any illnesses. These patients were immediately referred to Bajo hospital in Wangdue for the treatment.
For the treatment of Plasmodium falciparum cases, it takes eight days while plasmodium vivax takes 14 days.
The VDCP chief entomologist said as long as the team is in surveillance, follow-ups have to be done at certain fixed days to take the blood samples and check whether the parasites are still present in the blood or not.
The surveillance was also carried out last year in PHPA I where one malaria case was detected. About 1500 samples were screened randomly.
The chief Entomologist explained there are many factors for the cause of malaria in the project; the climate, temperature and humidity suitable for the mosquitoes to survive are main causes.
In addition the laborers are from different malaria endemic states in India all favorable for the spread of malaria.
Similar cases were also found in Indian laborers with eight cases in Bajo hospital.
However, the VDCP teams are still with the surveillance and targets to screen out at least 60 to 70% from the projects.