Borrelia in Ethiopian ticks

Two regions (Jimma and Dire Dawa) in Ethiopia were investigated for the presence of soft ticks. Although no Ornithodoros spp. ticks were collected during this survey, published records of their existence in Ethiopia were found. An overwhelming infestation of Argas persicus was revealed in a village located adjacent to Dire Dawa. These ticks primarily were feeding on poultry, but were also biting humans. Furthermore, hard ticks were collected from livestock and companion animals in these regions.Collected ticks were assessed for Borrelia by real-time PCR followed by conventional PCR and sequencing to identify species present. A. persicus ticks were found to carry B. anserina in 3 of 40 (7.5%) A. persicus tick pools, whilst hard tick pools yielded 2 of 16 (12.5%) positive for B. theileri. Collectively, these borrelial species and their tick vectors are likely to have an important economic impact of particular relevance to subsistence farmers in Ethiopia.     

Diversity and geographic distribution of rickettsial agents identified in brown dog ticks from across the United States

Rhipicephalus sanguineus sensu lato, or brown dog ticks, transmit a variety of pathogens of veterinary and public health importance globally. Pathogens vectored by brown dog ticks and identified in the United States include Babesia vogeli, Ehrlichia canis, and several spotted fever group Rickettsia spp. (SFGR). Due to the challenge of collecting canine blood samples nationwide to screen for exposure to these pathogens, we took an indirect approach and tested brown dog ticks for molecular evidence of infection. Brown dog ticks (616 adults and 65 nymphs) collected from dogs and cats across the nation were tested by separate PCR assays detecting Babesia spp., E. canis, and SFGR. While no Babesia sp. was found, we identified rickettsial agents in 3.5% (24/681; 95% CI 2.4–5.2%) of the ticks. Pathogens and related organisms detected in ticks included E. canis (n = 1), Rickettsia amblyommatis (n = 3), Rickettsia massiliae (n = 11), Rickettsia monacensis (n = 3), Rickettsia montanensis (n = 5), and an undefined Rickettsia species (n = 1). These data demonstrate a wider geographic distribution of R. massiliae than previously known, and to the authors’ knowledge, reports R. monacensis in brown dog ticks for the first time. Due to the close association that brown dog ticks have with domestic dogs and humans, more research is needed to understand the full array of organisms, some of which are zoonotic, potentially transmitted by this widespread tick complex.     

Genotypic evaluation of rickettsial isolates recovered from various species of ticks in Portugal.

Twelve rickettsial isolates, from Rhipicephalus sanguineus, R. turanicus, Dermacentor marginatus and Hyalomma marginatus, were subjected to genotypic analysis. Amplification of specific DNA sequences, restriction endonuclease digestion of amplified DNA products, and gel electrophoresis were used to identify specific DNA fragment-banding patterns. Five patterns were resolved. Four were homologous with those of previously described rickettsial genotypes, R. conorii, R. slovaca, R. rhipicephali and R. massiliae. The fifth pattern differed by only a single altered restriction endonuclease cleavage site. For the first time in Portugal a widely distributed spectrum of spotted fever group rickettsia was found among potential vector species stressing the need to determine their potential for human and domestic animals infection.     

Candidatus Rickettsia hoogstraalii in Ethiopian Argas persicus ticks

Ethiopian soft ticks Argas persicus, hard ticks including both Amblyomma variegatum and Rhipicephalus (Boophilus) spp., and fleas were collected from livestock, traditional human dwellings, and cracks and crevices of trees. They were assessed in pools for the presence of Rickettsia using PCR-based methods. The extracted tick DNA was subjected to molecular screening for Rickettsia, which revealed 50.5% of the pooled samples to be positive for Rickettsia spp. These were then subjected to multi-gene analysis using both outer surface proteins and housekeeping genes with proven discriminatory potential. Sequencing of the citrate synthase and outer membrane genes clearly led to the identification of three distinct rickettsial species, Candidatus Rickettsia hoogstraalii in Argas persicus ticks; R. africae in hard tick pools, and R. felis in fleas. Furthermore, we demonstrated the presence of the plasmid-borne small heat-shock protein gene hsp2 in DNA from A. persicus ticks suggesting that Candidatus R. hoogstraalii carried by these ticks possess a plasmid. Unlike chromosomal gene sequences, the hsp2 gene failed to cluster with Candidatus R. hoogstraalii, instead falling into an isolated separate clade, suggesting a different origin for the plasmid.     

A search for the epidemic typhus agent in Ethiopian ticks

The presence of antibodies to Rickettsia prowazeki in domestic animals from several parts of Africa, and the isolation of this rickettsia from the blood of goats and sheep and from ticks off cattle or camels in Ethiopia, led to the hypothesis that R. prowazeki in nature may occur in an extrahuman cycle involving ticks and domestic animals. This study attempted to recover R. prowazeki from 2 624 ticks (4 genera, 10 species) collected in central and southern Ethiopia. The ticks were examined by the haemolymph test and by the injection of tissues into guineapigs. No strains of typhus rickettsia were received and there was no serologic evidence suggesting the presence of this agent in any of the ticks examined. One Amblyomma cohaerens contained an organism that reacted specifically with fluorescing antibodies against R. prowazeki; attempts to isolate and identify this agent failed. Fifty-seven (2.2%) Amblyomma ticks (26 A. gemma, 17 A. variegatum, 14 A. cohaerens) were infected with rickettsiae of the spotted fever group, and probably represented R. conori or closely related rickettsial agents.     

Isolation ofCoxiella burnetii and of an unknown rickettsial organism fromIxodes ricinus ticks collected in Austria

Two strains ofCoxiella burnetii and two strains of an unidentified rickettsial organism were isolated for the first time fromIxodes ricinus ticks collected in the Alpine region of Tirol, Austria. TheC. burnetii strains belong to the group of agents causing acute forms of Q fever. The other two strains of isolated rickettsial agent share some antigenic epitopes withC. burnetii andR. prowazekii but they differ from them by their high sensitivity to freezing and refreezing and by poor multiplication in yolk sacs of chick embryos. There is at present no evidence that these organisms cause human illness and no ecological information is available. We suggest they may be some new species of rickettsiae or rickettsia-like organisms.     

Coping with Food Insecurity on a Micro-Scale: Evidence from Ethiopian Rural Households

This article examines the main household demographics and economic factors associated with food insecurity and coping behavior of rural households employed during times of food shortages in northern Ethiopia. Using a cost-of-basic-needs approach we estimated the food poverty line. This cut-off value was used to classify households as either food secure or insecure. Then empirical analyses were used, based on respectively a logit regression model and a coping strategy index. The estimated results revealed that household size, size of farm land, livestock ownership, frequency of extension services, and proximity to basic infrastructures are associated with the food security status of farming households in the study area. Moreover, households relied largely on consumption-based coping strategies when faced with food shortages.     

Residual agglutinins against rickettsial agents in human sera from central and eastern Turkey and their relation to cardiovascular diseases

Many workers have shown that the recrudescence of rickettsial infections may cause cardiovascular diseases of all kinds. As Turkey is a region where rickettsial infections in man are endemic, the relation between such infections and cardiovascular disease has been further studied there. Sera were collected from patients with cardiovascular diseases and also from healthy people and patients with diseases not affecting the heart, who served as a control group. A considerably higher percentage of positive sera was obtained from the patients with cardiovascular diseases, particularly for R. prowazekii, R. conorii and C. burnetii. It was also found that the highest percentage of positive sera was obtained from people in the 20-40 years age-group. Antistreptolysin-O (ASO) determinations were also made and it was found that, on average, agglutinin-negative sera had the higher ASO titres.     

Control of ticks resistant to immunization with Bm86 in cattle vaccinated with the recombinant antigen Bm95 isolated from the cattle tick, Boophilus microplus

The recombinant Bm86-containing vaccine Gavac(TM) against the cattle tick Boophilus microplus has proved its efficacy in a number of experiments, especially when combined with acaricides in an integrated manner. However, tick isolates such as the Argentinean strain A, show low susceptibility to this vaccine. In this paper we report on the isolation of the Bm95 gene from the B. microplus strain A, which was cloned and expressed in the yeast Pichia pastoris producing a glycosylated and particulated recombinant protein. This new antigen was effective against different tick strains in a pen trial, including the B. microplus strain A, resistant to vaccination with Bm86. A Bm95-based vaccine was used to protect cattle against tick infestations under production conditions, lowering the number of ticks on vaccinated animals and, therefore, reducing the frequency of acaricide treatments. The Bm95 antigen from strain A was able to protect against infestations with Bm86-sensitive and Bm86-resistant tick strains, thus suggesting that Bm95 could be a more universal antigen to protect cattle against infestations by B. microplus strains from different geographical areas.     

The spread of Q fever from animals to man; the natural history of a rickettsial disease

The authors review the sources of R. burneti in nature. The organism has been isolated in ticks, domestic and wild animals, and birds. The maintenance of the infection in nature is discussed. The epidemiology of Q fever in man, and the manner in which the infection is transmitted by domestic animals, are described.     

Assessing Community Health Information Systems: Evidence from Child Health Records in Food Insecure Areas of the Ethiopian Highlands

Maternal and Child Health Journal - This study assessed the completeness of child health records maintained and collected within community health information system in Ethiopia. A household listing...     

Validation of a serological test for the diagnosis of canine rickettsial disease

Canine vector borne diseases include a variety of illnesses affecting domestic dogs worldwide. Clinical abnormalities are often nonspecific during rickettsial infections, and coinfections caused by other tick-transmitted agents may be common. The aim of this study was to validate a differential serological assay for the diagnosis of rickettsial infections by the indirect fluorescent antibody (IFA) test. Sensitivity (DSe), specificity (Dsp), accuracy (Acc), positive and negative predictive values (PPV and NPV), positive and negative likelihood ratios (LR+ and LR?), Cohen's Kappa agreement, Youden's J index and odds values were calculated in order to define the positive and negative post-test probability and to establish a link between clinical signs compatible with a rickettsial infections and serological confirmation.     

Epidemiology of boutonneuse fever in western Sicily. Distribution and prevalence of spotted fever group rickettsial infection in dog ticks (Rhipicephalus sanguineus)

The distribution and prevalence of spotted fever group rickettsial infection in the ixodid dog tick Rhipicephalus sanguineus were found to occur at a rate of 19.7% with variation related to geographic and sociooccupational factors. A higher rate of infection was demonstrated in ticks removed from dogs associated with documented cases of boutonneuse fever. The results fit into available clinical and seroepidemiologic data on Rickettsia conorii infection in western Sicily.     

Seroepidemiology of rickettsial infections in Morocco

The prevalence of antibodies reactive withRickettsia conorii, Rickettsia typhi, Coxiella burnetii andEhrlichia chaffeensis was investigated using indirect immunofluorescence (IFA) test on human sera obtained from 300 blood donors in Casablanca and 126 sera obtained from clinical laboratories in Fez. In sera from Casablanca, antibodies reactive at titers >=1: 32 were found againstR. conorii (7%), andR. typhi (1.7%), but not againstE. chaffeensis. In the sera from Fez, antibodies were also detected againstR. conorii (5.6%),R. typhi (4%), but not againstE. chaffeensis. By Western immunoblotting, seroprevalence forR. conorii was in Casablanca and 4.8% in Fez. Antibodies reactive at titers >=1:50 againstC. burnetii (phase II) were present in sera from Casablanca (1%) and Fez (18.3%).Abbreviations IFA Immunofluorescence assay - MSF Mediterranean spotted fever - PBS Phosphate-buffered saline     

Deer ticks (Ixodes scapularis) and the agents of Lyme disease and human granulocytic ehrlichiosis in a New York City park.

Rodent trapping and drag sampling in Van Cortlandt Park, New York City, yielded all stages of Ixodes scapularis, the deer tick vector of Lyme disease and human granulocytic ehrlichiosis (HGE). Polymerase chain reaction analyses of the ticks showed Borrelia burgdorferi and the Ehrlichia sp. that causes HGE.     

Evidence for a high prevalence of spotted fever group rickettsial infections in diverse ecologic zones of Inner Mongolia.

A 3-year study of spotted fever group rickettsial ecology in Inner Mongolia revealed that nearly half of the human population tested had antibodies to Rickettsia sibirica detected by complement fixation test. Infected persons, ticks and a high proportion of seropositive livestock and wild rodents were found in all five vegetation zones (desert, steppe, forest, forest-grassland and grassland).     

宁波口岸蜱类及莱姆病病原体携带情况的调查研究

目的掌握宁波口岸蜱的种群特征和莱姆病病原携带情况。方法采用人工小时布旗法采蜱,用PCR法检测蜱类中携带的莱姆病DNA片段。结果采集蜱872只,隶属于1科3属3种,分别为中华硬蜱、长角血蜱、镰形扇头蜱,其中长角血蜱占97.36%,为优势种;3-9月均可捕获蜱,3-6月为高峰期,7月下旬种群数量开始急剧减少;莱姆病螺旋体DNA片段检测均呈阴性。结论查清宁波口岸蜱的种群结构,宁波口岸尚无莱姆病自然疫源地的证据。