The experimental study investigated the ability of tortoise tick Hyalomma aegyptium to play a role in forming and maintaining natural foci of Q fever. We tested the competence of H. aegyptium larvae to acquire Coxiella burnetii infection from mammals, serve as a C. burnetii vector between mammalian hosts, and be a long-term carrier of C. burnetii, including interstadial transmission. H. aegyptium larvae were allowed to feed on guinea pigs experimentally infected with C. burnetii. Engorged larvae molted to nymphs, some of which were preserved in 96% ethanol and later examined by polymerase chain reaction (PCR) using C. burnetii-specific primers (CBCOS, CBCOE). Prevalence of C. burnetii among these nymphs was 5.6% (n=235). Remaining nymphs then fed on other, C. burnetii-negative guinea pigs; and according to results of both, micro-agglutination reaction, and ELISA, they successfully transmitted C. burnetii to those new hosts. Detached engorged nymphs molted to adults, which were kept alive long term and then placed in 96% ethanol 383 days post-infection. Thereafter, they were examined by PCR in the same manner as were the nymphs. Prevalence of C. burnetii among adult H. aegyptium was 28.9% (n=90). According to our results, tortoise-specific ticks have indisputable potential in the epidemiology of Q fever natural foci.
It is the first time that Crimean-Congo haemorrhagic fever virus (CCHFV), causing potentially lethal disease of humans, has been reported from the Middle East region and from the tortoise tick Hyalomma aegyptium from a tortoise host, whose epidemiological significance may have remained almost completely overlooked so far. We used RT-PCR to screen for 245 ticks collected from 38 Testudo graeca tortoise individuals. Results of our genetic screening provide unambiguous evidence of occurrence of CCHFV in this region and host, suggesting a potentially important role of H. aegyptium in CCHF epidemiology.
Antimicrobial resistance (AMR) represents a serious problem globally, but it is especially pronounced in the tropics, where pressure of infectious diseases is high. We examined resistance in Escherichia coli colonizing gastrointestinal tracts of 17 dogs which have never received antimicrobial treatment, living in central rural Angola. Emphasis was placed on extended-spectrum beta-lactamases (ESBL) and plasmid-mediated quinolone resistance (PMQR). Resistance-carrying plasmids were characterized in size, group of incompatibility and ability to conjugate. Isolates were compared by their pulsed-field gel electrophoresis (PFGE) profiles. Detailed description of 19 E. coli isolates with either ESBL or PMQR genes carried on multiresistant plasmids of different groups of incompatibility indicates that dogs, despite never being treated by antibiotics, are important reservoirs and transmitters of AMR in the study area.
Distribution of Anaplasma spp., Babesia spp., Theileria spp., and Ehrlichia ruminantium, was for the first time studied in Bié Province, central Angola. We examined 76 blood samples of cattle originated from seven farms, and 13 blood samples of goats from two farms employing molecular genetic tools (PCR). Most prevalent was A. ovis-infection in goats (100%) and A. marginale-infection in cattle (38% of examined animals, and six out of seven farms). B. bigemina-infection was detected in only one specimen at Andulo, whereas B. bovis was not detected in Bié. We did not detected T. parva, the causative agent of serious diseases in cattle; nevertheless, infection by T. velifera was quite frequent (14% of examined animals, and five out of seven farms). Causative agent of heartwater disease – E. ruminantium, was not detected. Taking into account short-term perspective of PCR methods in monitoring of epidemiological status in herds, the number of infected animals and distribution of detected pathogens should not be ignored.
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