This study is the first detailed description of the diversity
of Anopheles species based on a molecular identification in
the two most malaria endemic areas of Thailand, Mae Sot
District in Tak Province and Sop Moei District in Mae Hong
Son Province, both located in the northwestern part of the
country that borders Myanmar. Results from this study
provide accurate species identification as well as seasonal
abundance and trophic behavior of Anopheles minimus and
Anopheles maculatus, among the most important malaria
vectors in northwestern Thailand.
In this study, six of the most important (primary and
secondary) malaria vector species in Thailand were collected.
The most abundant species in Mae Sot and Sop Moei was
An. minimus (42.8%), followed by An. maculatus (20.1%)
and An. sawadwongporni (5.5%). Collectively, these species
are responsible to varying degrees for maintaining malaria
transmission in both areas which have been listed as ‘A1’
areas by the Thai Ministry of Public Health, areas where
malaria occurs at least 6 months of the year and longer
(Chareonviriyaphap et al. 2001, BVBD 2013).
Anopheles minimus represented 43% of the total
Anopheles mosquitoes recorded from both areas during the
two-year collection period (53.4% in Mae Sot and 29.8% of
all anophelines in Sop Moei. Anopheles maculatus and An.
sawadwongporni were found in greater numbers compared to
An. pseudowillmori and An. dravidicus, all species within the
Maculatus Group. These findings are consistent with previous
observations in Mae Sot District (Tum Sua Village) that found
An. minimus to be the most abundant species (71%), followed
by An. maculatus Group (28%) and few specimens of the An.
dirus Complex (Tisgratog et al. 2012). Anopheles dirus and
An. baimaii, closely related and the most important forestrelated
malaria vectors, were found in very low densities
with only a total of 39 specimens collected in Mae Sot and
22 in Sop Moei during a two-year period. These two species
were slightly more common during the June collection both
years with only a few specimens detected other months.
Low collection numbers of the Dirus Complex complicate
drawing any definitive conclusions on host-seeking behavior
in this study.
In Thailand, the biting activity and behavior of specific
malaria vectors, based on reliable molecular identification
methods, has been studied in detail in relatively fewer instances
compared to earlier studies that based all identification on
morphological characters alone. For example, two species