Survey and Phylogenetic Analysis of Leucocytozoon (Apicomplexa: Haemosporida) Parasites in Mississippi Black Flies (Diptera: Simuliidae).

For several years, there have been continuous reports of black flies in Mississippi with evidence of transmission of Leucocytozoon spp. This study was conducted to determine the presence and diversity of Leucocytozoon spp. in black flies captured throughout Mississippi. Thirty-three collections, consisting of 346 specimens, were made during the 2-yr period (2015-2016) at 10 locations around the state. In addition to these systematic biweekly collections, 46 specimens were taken in 10 collections at four additional sites from 2009 to 2014, as well as 388 specimens taken in 14 collections during a severe black fly outbreak during March and April of 2018. Out of 186 pooled samples, 21 samples were positive for haemosporidian DNA. Eighteen of those samples were identified as Leucocytozoon spp. A phylogenetic tree was constructed using the novel sequences along with existing sequences from the MalAvi database. Results showed several of the sequences constructed in this study had high divergence from the existing sequences from the database.

Seasonality of Aedes albopictus in North and Central Mississippi.

Container-breeding mosquitoes are increasingly important in public health due to recent outbreaks of Zika virus, chikungunya, and dengue. This paper documents seasonality of the most prevalent container-breeding mosquito species in Mississippi-Aedes albopictus. Ten sites in 5 counties in both northern and central Mississippi (20 sites, 10 counties total) were sampled by larval dipping and oviposition traps biweekly from September 2016 to June 2019, totaling 22 months and potentially yielding 440 egg or larval collections. However, 22 collections were missed due to inclement weather and personnel issues during the study period, so actually only 418 site visits were performed. Sites were chosen to maximize chances of finding Ae. albopictus. Of the total 1,310 mosquito larvae collected during the study period, 717 larvae and 50 positive egg papers belonged to Ae. albopictus. Aedes albopictus was found in all 10 northern and central counties. No eggs were collected at any of the sites from December through February, although larvae were occasionally collected during that time frame. This study demonstrates that Ae. albopictus is active in central and northern Mississippi beginning in March each year and continuing through November or December. There is little activity during the coldest months of the year (January and February). These data represent the first extensive analysis of Ae. albopictus seasonality in Mississippi, and as such, allow for better public health awareness of diseases transmitted by this species and design of more effective vector control programs.

Insecticide Resistance Testing of Culex quinquefasciatus and Aedes albopictus from Mississippi.

Data on insecticide resistance in mosquitoes from Mississippi are reported. Mosquitoes were collected from June through October 2017 from 28 cities in Mississippi and included wild-caught Culex quinquefasciatus Say obtained as egg rafts (reared to adults), and Aedes albopictus (Skuse) collected as larvae (reared to adults). The Centers for Disease Control and Prevention (CDC) bottle bioassay protocol was utilized. Thirty-six populations of Cx. quinquefasciatus were tested for malathion resistance from 24 cities; 22 of them (61.1%) met the World Health Organization criteria as resistant, and the remaining 14 (38.9%) were classified suspected resistant. Forty-one populations of Cx. quinquefasciatus were also tested from 24 cities for resistance to permethrin, and of these, 18 populations (43.9%) were susceptible, 13 (31.7%) were resistant, and 10 (24.4%) were suspected resistance. Eighteen populations of Ae. albopictus were collected from 10 cities in Mississippi for resistance testing to malathion; 5 populations were susceptible (27.8%), 5 were resistant (27.8%), and 8 (44.4%) suspected resistant. Sixteen populations of Ae. albopictus were tested from 10 cities for resistance to permethrin and none were resistant.