Investigation of Transovarial Transmission of Bartonella henselae in Rhipicephalus sanguineus sensu lato Ticks Using Artificial Feeding

Bartonella henselae is a slow-growing, Gram-negative bacterium that causes cat scratch disease in humans. A transstadial transmission of the bacteria from larvae to nymphs of Rhipicephalus sanguineus sensu lato (s.l.) ticks, suspected to be a potential vector of the bacteria, has been previously demonstrated. The present study aims to investigate transovarial transmission of B. henselae from R. sanguineus s.l. adults to their instars. Adult ticks (25 males and 25 females) were fed through an artificial feeding system on B. henselae-infected goat blood for 14 days, and 300 larvae derived from the experimentally B. henselae-infected females were fed on noninfected goat blood for 7 days. Nested PCR and culture were used to detect and isolate B. henselae in ticks and blood samples. Bartonella henselae DNA was detected in midguts, salivary glands, and carcasses of the semi-engorged adults and pooled tick feces (during feeding and post-feeding periods). After the oviposition period, B. henselae DNA was detected in salivary glands of females (33.3%), but not in pooled eggs or larvae derived from the infected females. However, B. henselae DNA was detected by nested PCR from the blood sample during larval feeding, while no viable B. henselae was isolated by culture. According to our findings, following infected blood meal, B. henselae could remain in the tick midguts, move to other tissues including salivary glands, and then be shed through tick feces with limited persistency. The presence of bacterial DNA in the blood during larval feeding shows the possibility of transovarial transmission of B. henselae in R. sanguineus s.l. ticks.

897Environmental contamination of Coxiella burnetii in and around an endemically infected goat farm

Background Coxiella burnetii is the cause of Q fever, a zoonotic disease spread by aerosol transmission. This study investigated C. burnetii environmental contamination in and around an endemically infected, intensively managed dairy goat farm in Victoria, Australia. Methods Dust, soil and water were collected in and around kidding pens. Samplings were collected before, during and after each kidding season. Soil was sampled along a 500 m transect from the main kidding pen in the predominant wind direction to assess the risk of C. burnetii spread from the main farm shed as a point source. DNA extraction and quantitative PCRs targeting the IS1111 and com1 genes were performed. Analyses are ongoing to describe the change in the frequency of C. burnetii positive environmental samples as a function of distance from the main farm shed. Results Dust inside the kidding pen contained C. burnetii DNA at all time points, with higher loads during the kidding seasons. Soil samples were positive for both PCR targets and were evenly dispersed within close ranges (500 m) from the main farm shed. Only those water samples taken from close to the main farm shed were positive. Conclusions C. burnetii was readily found in dust and soil in and around a farm shed where coxiellosis was endemic. Further environmental sampling will allow us to estimate the distance over which C. burnetii contamination occurs around a known point source. Key messages Results of this study will provide information critical for estimating Q fever risk around livestock facilities.

Analysis of recombinant proteins for Q fever diagnostics

Serology is essential for Q fever diagnostics, a disease caused by the bacterial pathogen Coxiella burnetii. The gold standard test is an immunofluorescence assay utilizing whole cell antigens, which are both dangerous and laborious to produce. Complexities of the antigen coupled with the subjective nature of the assay lead to decreased uniformity of test results and underscore the need for improved methodologies. Thirty-three C. burnetii proteins, previously identified as immunoreactive, were screened for reactivity to naturally infected goat serum. Based on reactivity, 10 proteins were analyzed in a secondary screen against human serum from healthy donors. Assay sensitivity and specificity ranged from 21 to 71% and 90 to 100%, respectively. Three promising antigens were identified based on receiver operating characteristic curve analysis (CBU_1718, CBU_0307, and CBU_1398). Five multiplex assays failed to outperform the individual proteins, with sensitivities and specificities ranging from 29 to 57% and 90 to 100%, respectively. Truncating the top antigen, CBU_1718, had no effect on specificity (90%); yet sensitivity decreased dramatically (71% to 21%). Through this study, we have expanded the subset of C. burnetii immunoreactive proteins validated by enzyme-linked immunosorbent assay and demonstrate the effect of novel antigen combinations and protein truncations on assay performance.

Comparative histomorphological study of non affected and affected bile duct and gall bladder by fascioliasis in Black Bengal Goat

The purpose of this study was to comparative histomorphological investigation of the non affected and affected bile duct and gall bladder by fascioliasis in Black Bengal goat. The average weight of affected gall bladder was 26.10±0.70 gm which was significantly (p<0.001) higher than non affected gall bladder (19.40±0.96 gm). The average length and girth of affected gall bladder were 10.30±0.37 cm and 8.24±0.30 cm, respectively which were also significantly (p<0.001) higher than the length (6.10±0.30 cm) and Girth (5.85±0.25 cm) of non-affected gall bladder of Black Bengal Goat. The gross changes in acute form, thickening of the bile ducts and fibrosis in a portal area due to chronic fascioliasis was found in case of affected bile duct but were not found in case of non affected liver. A brownish exudates and a number of mature Fasciola gigantica were found in the lumen. The adult Fasciola gigantica was noticed in cross section in the lumen of the thickened bile ducts. Acute pathological lesions could only be produced by developing flukes prior to their entry to the bile ducts. Microscopically the epithelial layer of the bile ducts were seen to the partially disintegrated, but simultaneous proliferation of epithelial cells occurred. Thickening of the bile ducts was the result of connective tissue proliferation. Deposition of bile pigment in the tissue space and bile duct in some parts showed periductal cellular infiltrations, mainly neutrophiles, lymphocyte and eosinophiles. No calcification in the wall of the bile ducts in chronic Fascioliasis in goat could be seen in this study. The gall bladder was very dark usually contained blood clots, the consistency of bile was also very dense. Microcopically hyperplasia of the tubuloalveolar glands and numerous eggs were seen in the bile of infected goat which were absence in case of non infected goat. Asian J. Med. Biol. Res. December 2018, 4(4): 406-415