Development and evaluation of a chemiluminescence immunoassay for detecting tropical theileriosis.

Tropical theileriosis is a tick-borne lymphoproliferative disease of cattle caused by the apicomplexan parasite Theileria annulata, and leads to substantial economic losses to the livestock industry worldwide. Although various enzyme-linked immunosorbent assays (ELISAs) have been established to detect antibodies against T. annulata infection, a specific, rapid and reliable diagnostic assay is urgently needed for prevention and control of the disease. In the present study, a chemiluminescence immunoassay (CLIA) was developed based on the subtelomeric variable secreted protein (SVSP) of T. annulata as a sero-diagnostic antigen. Following optimization of the CLIA working parameters, the working time of the method was less than 4.5 h. The sensitivity and specificity of the established CLIA was 98.8% and 97.5%, respectively, when the cut-off value of the percent positive (PP) was 26.1% for detecting serum samples (n = 242 T. annulata positive sera, n = 158 T. annulata negative sera). After comparing 180 serum samples from Gansu province, China, the concordance rate between the CLIA and a published rSpm2 ELISA method was 72.8%. In addition, 565 serum samples of cattle collected between 2017 and 2018 from four provinces in China were detected by the CLIA, and the seroprevalence for T. annulata ranged from 53.3% to 67.3% in these regions. Our findings demonstrated that the CLIA has high specificity, sensitivity and reliability, and could be used as a rapid detection assay for epidemiological investigations of T. annulata infection.

Serological occurrence for tick-borne agents in beef cattle in the Brazilian Pantanal / Ocorrência sorológica para agentes transmitidos por carrapatos em bovinos de corte no Pantanal Brasileiro

Abstract This study investigated the seropositivity for five different tick-borne agents, namely Anaplasma marginale, Babesia bovis, Babesia bigemina, Coxiella burnetii, Anaplasma phagocytophilum, and Trypanosoma vivax in beef cattle in the Brazilian Pantanal. The serum samples collected from animals (200 cows; 200 calves) were used in indirect enzyme-linked immunosorbent assays (iELISA) to detect IgG antibodies against A. marginale, B. bovis, B. bigemina, and T. vivax, and Indirect Fluorescent Antibody Test (IFAT) for detecting IgG antibodies against C. burnetii and A. phagocytophilum. No correlation was observed between seropositivity for C. burnetii and A. phagocytophilum with other agents whereas moderate correlation was observed for A. marginalexB. bigemina x B. bovis. Cows were more seropositive for T. vivax whereas calves were more seropositive for B. bovis and B. bigemina. The highest number of seropositive animals by a single agent was observed for T. vivax (15.2%). Co-seropositivity for T. vivax + A. marginale was higher in cows (25.5%) and for T. vivax + B. bovis + B. bigemina + A. marginale was higher in calves (57.5%). The high seropositivity correlation for A. marginale x B. bovis x B. bigemina is probably due to the presence of the tick biological vector, Rhipicephalus microplus, in the studied farms. Common transmission pathways, mediated by hematophagous dipterans and fomites, may explain the high co-seropositivity of cows for A. marginale and T. vivax. Low seropositivity to C. burnetii is probably due to the type of breeding system employed (extensive). Seropositivity for A. phagocytophilum in only one animal suggests the occurrence of a cross-serological reaction with another agent of the genus Anaplasma.

Resumo Este estudo teve como objetivo determinar a co-soropositividade para agentes transmitidos por carrapatos, como Anaplasma marginale, Babesia bovis, Babesia bigemina, Coxiella burnetii, Anaplasma phagocytophilum, e Trypanosoma vivax em bovinos de corte do Pantanal Brasileiro. Amostras de soro foram colhidas de 400 animais (200 vacas; 200 bezerros) e submetidas a Ensaios Imunoenzimáticos Indiretos (iELISA) para detecção de anticorpos IgG anti- A. marginale, anti- B. bovis, anti- B. bigemina e anti- T. vivax, e à Reação de Imunofluorescência Indireta (RIFI) para detecção de anticorpos IgG anti -C. burnetii e anti- A. phagocytophilum. Ausência de correlação foi vista entre os animais soropositivos para C. burnetii e A. phagocytophilum com os outros agentes e correlação moderada ocorreu entre A. marginale x B. bigemina x B. bovis. Vacas foram mais soropositivas que bezerros para T. vivax e bezerros mais soropositivos que vacas para B. bovis e B. bigemina. Maior número de animais soropositivos para um único agente foi visto para T. vivax (15,2%). Vacas demonstraram maior co-soropositividade para T. vivax + A. marginale (25,5%) e bezerros para T. vivax + B. bovis + B. bigemina + A. marginale (57,5%). A alta correlação entre a soropositividade para A. marginale x B. bovis x B. bigemina é provavelmente devida à presença do vetor biológico, o carrapato Rhipicephalus microplus, nas fazendas estudadas. As vias de transmissão comuns, mediadas por dípteros hematófagos e fômites, podem explicar a alta co-soropositividade das vacas para A. marginale e T. vivax. A baixa soropositividade para C. burnetii é provavelmente devida ao tipo de sistema de criação empregado (extenso). A soropositividade para A. phagocytophilum em apenas um animal sugere a ocorrência de reação sorológica cruzada com outro agente do gênero Anaplasma.

Seroprevalence of six pathogens transmitted by the Ixodes ricinus ticks in asymptomatic individuals with HIV infection and in blood donors.

The objective of our study was to estimate the seroprevalence of six pathogens transmitted by ticks in HIV-infected persons and blood donors in Poland (B. burgdorferi s.l., A. phagocytophilum, Ehrlichia spp., Babesia spp., Rickettsia spp. Bartonella henselae) to assess the frequency of exposure to such microorganisms in immunocompetent and immunocompromised individuals in endemic regions for I. ricinus ticks. Serum samples were collected from 227 HIV-infected patients and 199 blood donors. All samples were analyzed for antibodies against six tick-borne pathogens and seroprevalence rates were statistically compared between two tested group as well as age, sex and lymphocyte T CD4+ level in HIV infected patients. The seroprevalence of tick-borne infections in HIV-infected patients is higher than that of the healthy population in Poland, although no association between serological status of patients and lymphocyte CD4+ T cell level has been observed. The frequency of tick-borne coinfections and doubtful results of serological tests were significantly higher in HIV-positive individuals. In Poland, the possibility of tick-borne diseases transmission with blood is rather negligible.

Characterization of the Theileria parva sporozoite proteome.

East Coast fever is a lymphoproliferative disease caused by the tick-borne protozoan parasite Theileria parva. The sporozoite stage of this parasite, harboured and released from the salivary glands of the tick Rhipicephalus appendiculatus during feeding, invades and establishes infection in bovine lymphocytes. Blocking this initial stage of invasion presents a promising vaccine strategy for control of East Coast fever and can in part be achieved by targeting the major sporozoite surface protein p67. To support research on the biology of T. parva and the identification of additional candidate vaccine antigens, we report on the sporozoite proteome as defined by LC-MS/MS analysis. In total, 4780 proteins were identified in an enriched preparation of sporozoites. Of these, 2007 were identified as T. parva proteins, representing close to 50% of the total predicted parasite proteome. The remaining 2773 proteins were derived from the tick vector. The identified sporozoite proteins include a set of known T. parva antigens targeted by antibodies and cytotoxic T cells from cattle that are immune to East Coast fever. We also identified proteins predicted to be orthologs of Plasmodium falciparum sporozoite surface molecules and invasion organelle proteins, and proteins that may contribute to the phenomenon of bovine lymphocyte transformation. Overall, these data establish a protein expression profile of T. parva sporozoites as an important starting point for further study of a parasitic species which has considerable agricultural impact.

A tiny tick can cause a big health problem.

Ticks are tiny crawling bugs in the spider family that feed by sucking blood from animals. They are second only to mosquitoes as vectors of human disease, both infectious and toxic. Infected ticks spread over a hundred diseases, some of which are fatal if undetected. They spread the spirochete (which multiplies in the insect's gut) with a subsequent bite to the next host. We describe the only reported cases of peri ocular tick bite from India that presented to us within a span of 3 days and its management. Due suspicion and magnification of the lesions revealed the ticks which otherwise masqueraded as small skin tags/moles on gross examination. The ticks were firmly latched on to the skin and careful removal prevented incarceration of the mouth parts. Rickettsial diseases that were believed to have disappeared from India are reemerging and their presence has recently been documented in at least 11 states in the country. Among vector borne diseases, the most common, Lyme disease, also known as the great mimicker, can present with rheumatoid arthritis, fibromyalgia, depression, attention deficit hyperactivity disorder, multiple sclerosis, chronic fatigue syndrome, cardiac manifestations, encephalitis, and mental illness, to name some of the many associations. Common ocular symptoms and signs include conjunctivitis, keratitis, uveitis, and retinitis. Early detection and treatment of tick borne diseases is important to prevent multi system complications that can develop later in life.

Epidemiological, clinical, and laboratory characteristics of 48 cases of "Babesia venatorum" infection in China: a descriptive study.

BACKGROUND: Human babesiosis is an emerging zoonosis. "Babesia venatorum" has been identified in only four asplenic men and a child so far. We aimed to describe the epidemiological, clinical, and laboratory characteristics of a series of cases with "B venatorum" infection identified in a sentinel hospital in China. METHODS: We recruited participants with a recent tick bite at Mudanjiang Forestry Central Hospital, Heilongjiang province, China. Cases were diagnosed through PCR followed by sequencing, microscopic identification, or isolation by animal inoculation, or both. FINDINGS: 48 individuals (30 women or girls; median age 45 years, range 7 months to 75 years) with "B venatorum" infection were identified. 32 of these individuals were confirmed cases and 16 were probable cases. None of the 48 cases had received a blood transfusion or had a splenectomy. Geographically, cases were distributed diffusely throughout the hospital catchment area. Of the 32 confirmed cases, 21 (66%) presented with a fever, 13 (41%) with a headache, 12 (38%) with myalgia or arthralgia, and three (9%) with chills. 14 (44%) patients had fatigue, eight (25%) had dizziness, and eight (25%) had hypersomnia. Six (19%) patients had an erythematous non-pruritic rash around the tick-bite site and two (6%) had lymphadenopathy. Seven (22%) and four (13%) patients had anaemia and thrombocytopenia, respectively, and seven (50%) of 14 patients with confirmed infection had increased hepatic transaminase concentrations. In the confirmed cases, concentrations of intercellular adhesion molecule 3 (p<0·001), P-selectin (p<0·05), and platelet endothelial cell adhesion molecule 1 (p<0·001) were significantly reduced, whereas tumour necrosis factor α (p<0·01) and vascular cell adhesion molecule 1 (p<0·001) were significantly increased. INTERPRETATION: "B venatorum" infection should be included in the differential diagnosis of patients with a tick-exposure history in areas where this pathogen has previously been identified in ticks or people. FUNDING: Natural Science Foundation of China and Mega-Project for Infectious Diseases.

In vitro titration of Theileria parva tick derived stabilates.

Immunization against the protozoan Theileria parva by infection and treatment has proved to be very efficient for the control of East Coast fever, an acute and often-fatal lymphoproliferative tick-borne disease of cattle in Eastern, Central and Southern Africa. The immunizing dose of live T. parva sporozoites used in this method is usually determined by in vivo titration. An alternative in vitro method of quantification of sporozoites in whole tick-derived stabilates is proposed. The method consists of incubating serially diluted T. parva stabilates with bovine peripheral blood lymphocytes, the host cell that is infected naturally. Allowing the cultures to incubate undisturbed for the full cultivation period (10 days) reduced the variability among replicate titrations. Fungal contaminations were avoided by centrifuging stabilates at 400 g prior to the incubation, which did not precipitate sporozoites significantly. Fungistatics, Nystatin and Flucytosine, did not appear to interfere with the in vitro development of T. parva but their effect on fungal growth was limited. In vitro titration data were compared to in vivo infection data for 2 stabilates. In vitro titration of T. parva sporozoites should allow more ethical and efficient research on the preparation and storage of T. parva tick-derived stabilates.

[Microscopic diagnosis of tick-borne diseases in Maghreb]. / Diagnostic microscopique des maladies transmises par les tiques au Maghreb.

Direct microscopic examination of smears, carried out in the farm, in combination with the clinical symptoms, is in general the quickest and cheapest way to diagnose tick-borne diseases. It is however not always sufficiently specific, as different species of a parasite genus may ressemble each other morphologically. Also, it is not suitable for epidemiological studies. On the other hand, serological and molecular methods may be more sensitive and/or specific, but are not suitable for diagnosing the cause of disease in an individual animal and in any case are not sufficiently rapid. The focus of the paper is on practical details and pitfalls to be avoided in sample taking, smear preparation, fixing and staining, microscopic examination and interpretation of the results

Canine hepatozoonosis: comparison of lesions and parasites in skeletal muscle of dogs experimentally or naturally infected with Hepatozoon americanum.

We report previously undescribed, early lesions in skeletal muscle of dogs experimentally infected with Hepatozoon americanum by ingestion of laboratory-reared, infected Amblyomma maculatum. The earliest muscle lesion was recognized at the first interval of examination 3 weeks following exposure. The lesion consisted of a large, modified host cell whose cytoplasm frequently contained a demonstrable parasite. In skeletal muscle, the cell was consistently located between muscle fibers or in loose connective tissue adjacent to those fibers. Evidence suggesting that the parasite arrives in muscle and other tissue within the host cell cytoplasm is presented. Mucopolysaccharide encystment of the host cell, absent at this early stage, was acquired gradually and approached maximal development 26 weeks post exposure. Completion of the asexual cycle as evidenced by the presence of parasites entering vascular lumens within granulomas and also by the presence of gamonts in peripheral blood leukocytes, occurred within 28-32 days postexposure. Progression of the parasite cycle from meront to passage of zoites into vessel lumens of granulomas can occur in 11 or fewer days. The density with which parasitic lesions occur in one named skeletal muscle compared to other named muscles, although somewhat variable, was not significantly different in either experimentally induced or natural infections. The distribution of developmental stages of the parasite/lesion in four experimental infections (969 lesions) is compared with those in eight dogs with natural infections (557 lesions).