ABSTRACT
Objective@#To carry out a investigation on molecular epidemiological features of tick-borne Brucella in Xinjiang Uygur Autonomous Region (Xinjiang), and to provide a scientific basis for formulation of effective preventive and control measures.@*Methods@#In 2016-2018, parasitic ticks (including engorged females) were collected on the body surface of livestock in 10 counties (cities) along the border of Xinjiang. The free-living ticks were collected by flagging method in Alashankou. The engorged female was placed in a breathable insect tube for spawning, each egg batch was divided into two parts: one part was tick eggs, while the second part was allowed further larval development. All ticks were identified by molecular biology (16S rRNA) identification. Tick DNA was extracted, PCR was performed based on Brucella omp22 and IS711, and amplification products were sequenced and analyzed by BLAST.@*Results@#A total of 1 084 ticks were collected in 11 counties (cities), of them 747 were parasitic ticks (including 34 engorged females) and 337 were free-living ticks. Based on 16S rRNA identification, 1 084 ticks belonged to 4 genera and 5 species, and the proportions of Dermacentor nuttalli, Dermacentor marginatus, Haemaphysalis punctata, Hyalomma asiaticum and Rhipicephalus turanicus were 29.43% (319/1 084), 16.51% (179/1 084), 10.42%(113/1 084), 37.27% (404/1 084), and 6.37% (69/1 084), respectively. A total of 214 Brucella-positive nucleic acid samples were detected, the positive rate was 19.74%. The parasitic ticks' positive rate was 25.30% (189/747), and the free-living ticks' positive rate was 7.42% (25/337), parasitic ticks' positive rate was higher than that of free-living ticks (χ2=46.873, P < 0.05). Two Brucella melitensis nucleic acid samples were detected in 34 "engorged females-tick eggs" developmental stage, and one Brucella melitensis nucleic acid sample was detected in 22 "tick eggs-larvae" developmental stage.@*Conclusions@#Brucella is widely distributed in parasitic ticks and free-living ticks in Xinjiang border areas, and the parasitic ticks' positive rate is obviously higher than that of free-living ticks. The Brucella melitensis has potential transovarian transmission and transstadial transmission in ticks. In the prevention and control of livestock brucellosis, the work of killing ticks should be strengthened, including parasitic ticks on the body surface and free-living ticks in the environment.
ABSTRACT
Objective To carry out a investigation on molecular epidemiological features of tick-borne Brucella in Xinjiang Uygur Autonomous Region (Xinjiang), and to provide a scientific basis for formulation of effective preventive and control measures. Methods In 2016 - 2018, parasitic ticks (including engorged females) were collected on the body surface of livestock in 10 counties (cities) along the border of Xinjiang. The free-living ticks were collected by flagging method in Alashankou. The engorged female was placed in a breathable insect tube for spawning, each egg batch was divided into two parts: one part was tick eggs, while the second part was allowed further larval development. All ticks were identified by molecular biology (16S rRNA) identification. Tick DNA was extracted, PCR was performed based on Brucella omp22 and IS711, and amplification products were sequenced and analyzed by BLAST. Results A total of 1084 ticks were collected in 11 counties (cities), of them 747 were parasitic ticks (including 34 engorged females) and 337 were free-living ticks. Based on 16S rRNA identification, 1084 ticks belonged to 4 genera and 5 species, and the proportions of Dermacentor nuttalli, Dermacentor marginatus, Haemaphysalis punctata, Hyalomma asiaticum and Rhipicephalus turanicus were 29.43％ (319/1084), 16.51％ (179/1084), 10.42％(113/1084), 37.27％ (404/1084), and 6.37％ (69/1084), respectively. A total of 214 Brucella-positive nucleic acid samples were detected, the positive rate was 19.74％. The parasitic ticks' positive rate was 25.30％ (189/747), and the free-living ticks' positive rate was 7.42％ (25/337), parasitic ticks' positive rate was higher than that of free-living ticks (χ2 = 46.873, P < 0.05). Two Brucella melitensis nucleic acid samples were detected in 34 "engorged females-tick eggs" developmental stage, and one Brucella melitensis nucleic acid sample was detected in 22 "tick eggs-larvae" developmental stage. Conclusions Brucella is widely distributed in parasitic ticks and free-living ticks in Xinjiang border areas, and the parasitic ticks' positive rate is obviously higher than that of free-living ticks. The Brucella melitensis has potential transovarian transmission and transstadial transmission in ticks. In the prevention and control of livestock brucellosis, the work of killing ticks should be strengthened, including parasitic ticks on the body surface and free-living ticks in the environment.
ABSTRACT
Background & objectives: The susceptibility of the mosquito to the invading pathogen is predominantly dictated by the complex interactions between the mosquito midgut and the surface proteins of the invading pathogen. It is well documented that the midgut microbiota plays an important role in determining the susceptibility of the mosquito to the pathogen. In the present study, we investigated the influence of Serratia odorifera, an endogenous cultivable midgut inhabitant of Aedes aegypti on the chikungunya virus (CHIKV) susceptibility to this mosquito. Methods: Ae. aegypti females free of gutflora were co-fed with CHIKV and either of the two midgut inhabitants namely, S. odorifeara and Microbacterium oxydans. CHIKV dissemination was checked on 10th day post feeding (DPF) using indirect immunoflurescence assay and plaque assay. CHIKV interacting proteins of the mosquito midgut were identified using virus overlay protein binding assay and MALDI TOF/TOF analysis. Results: The observations revealed that co-feeding of S. odorifera with CHIKV significantly enhanced the CHIKV susceptibility in adult Ae. aegypti, as compared to the mosquitoes fed with CHIKV alone and CHIKV co-fed with another midgut inhabitant, M. oxydans. Virus overlay protein binding assay (VOPBA) results revealed that porin and heat shock protein (HSP60) of Ae. aegypti midgut brush border membrane fraction interacted with CHIKV. Interpretation & conclusions: tThe results of this study indicated that the enhancement in the CHIKV susceptibility of Ae. aegypti females was due to the suppression of immune response of Ae. aegypti as a result of the interaction between S. odorifera P40 protein and porin on the gut membrane.