Prevalence of culicine salivary antibodies in non-human primates living in national parks in Thailand

Macaques are widely distributed in Thailand with remarkable adaptation to living close to humans in residential, religious sites, markets, and tourist areas. They play an essential role in the persistence of pathogens in the environment. As reservoir hosts, they are exposed to hematophagous vectors that secrete saliva, a cocktail of bioactive molecules including antigenic components stimulating host antibody production. Subsequent to the detection of mosquito-borne pathogens in macaques living in national parks, we aimed to determine the seroprevalence of antibodies to crude salivary gland extracts (SGE) from culicine mosquitoes (Aedes aegypti [Linnaeus, 1762], Ae. albopictus [Skuse, 1895], and Culex quinquefasciatus [Say, 1823]) and compare individual titers between macaque species/national parks (33, Macaca arctoides [I.Geoffroy Saint-Hilaire, 1831] [Primates: Cercopithecidae] from Kaeng Krachan, 23 M. leonina leonina [Blyth, 1863] [Primates: Cercopithecidae] from Khao Yai, and 4 M. fascicularis [Raffles, 1821] [Primates: Cercopithecidae] from Mu Ko Ranong). The anti-mosquito SGE antibodies found in 60 macaques from three national parks indicate varying levels of host-vector exposure. Macaque antibody titers were high against culicine mosquitoes. However, the significant difference among national parks (or macaque species) was only observed against Cx. quinquefasciatus. Correlation analysis of titers between Aedes SGE and arboviruses revealed a significantly more intense immune response against Ae. albopictus in DENV3-positive M. arctoides. Current findings support the concept of salivary biomarkers using accessible SGE, available from mosquito colonies of interest. However, we observed cross-reactivity between Aedes species because of crude SGE containing species-shared proteins. Nevertheless, a potential risk of pathogen transmission is emphasized between national park visitors and macaques via mosquitoes as bridge vectors. This information contributes to preventive measures against mosquito bites, including those implemented in tourist areas.

Methods
All data sets of antibody titers of macaque bloods, mosquito salivary grand extraction protein profiles, and PRNT titers of virus detections were recored in Microsolf excel spreed sheet solfware, USA.