RESUMEN

Contamination of food chains by toxigenic fungi and aflatoxins is a global problem that causes damage to human health, as well as to crop and livestock production. The objective is to evaluate Aspergillus flavus and total aflatoxins (AFs) occurrence in totally mixed rations (TMRs) for dairy cows and aflatoxin M1 (AFM1) in milk for human consumption. Ninety-nine dairy production units located in Aguascalientes, Mexico, were randomly selected, and samples were collected from TMRs, raw milk, and milk marketed in the city in two consecutive agricultural cycles. AFs were quantified in TMRs and milk by indirect enzyme immunoassay and HPLC; aflatoxigenic and molecular (PCR) capacity of monosporic A. flavus isolates in the feed was characterized. All feed, raw, and pasteurized milk samples showed aflatoxin contamination (26.0 ± 0.4 µg/kg, 32.0 ± 1.0, and 31.3 ± 0.7 ng/L, respectively), and a significant proportion (90.4, 11.3, and 10.3%) exceeded the locally applied maximum permissible limits for feed and milk (20.0 µg/kg and 50 ng/L). Aflatoxin contamination in both TMRs and milk indicated a seasonal influence, with a higher concentration in the autumn-winter cycle when conditions of higher humidity prevail. The results obtained suggest the existence of contamination by aflatoxigenic A. flavus and aflatoxins in the diet formulated for feeding dairy cows and, consequently, in the dairy food chain of this region of the Mexican Highland Plateau.

Asunto(s)

Aflatoxina M1 , Aflatoxinas , Aflatoxina M1/análisis , Aflatoxinas/análisis , Animales , Aspergillus flavus , Bovinos , Femenino , México , Leche/química

RESUMEN

The datasets of records of the distribution of ticks and their hosts are invaluable tools to understand the phylogenetic patterns of evolution of ticks and the abiotic traits to which they are associated. Such datasets require an exhaustive collection of bibliographical references. In most cases, it is necessary the confirmation of reliable identification of ticks, together with an update of the scientific names of the vertebrate hosts. These data are not easily available, because many records were published in the so-called "grey literature". Herein, we introduced the Dataset of Ticks in South America, a repository that collates data on 4,764 records of ticks (4,124 geo-referenced) with a special reference to an extra 2,370 records of ticks on cattle, together with a set of abiotic traits, curated from satellite-derived information over the complete target region. The dataset includes details of the phylogenetic relationships of the species of hosts, providing researchers with both biotic and abiotic traits that drive the distribution and evolution of ticks in South America.

Asunto(s)

Bovinos/parasitología , Filogenia , Garrapatas/clasificación , Animales , América del Sur

RESUMEN

Rhipicephalus microplus (formerly Boophilus microplus) ticks are potential vectors of several pathogens of livestock especially in tropical and subtropical regions where may have substantial effects on economic development. Among tick-borne pathogens, Anaplasma marginale is considered one of the most important in domestic and wild ruminants worldwide. Different molecular mechanisms have been employed by both ticks and these intracellular pathogens, in order to be able to adapt and survive. Subolesin, originally called 4D8, is an evolutionarily well-preserved protein among ixodid tick species. This new antigen was found to be protective against tick infestations when used as a vaccine, as it has an essential role in tick blood digestion, development and infection of host cells by A. marginale. Recent studies have demonstrated that infection of both tick and vertebrate host cells with this microorganism changed gene expression. Therefore, the main objective of this study was to investigate subolesin expression in uninfected and A. marginale-infected R. microplus salivary glands by real-time reverse transcriptase (RT)-PCR. To analyze the differential expression of the recombinant protein subolesin, the gene was previously expressed from ticks infected with A. marginale. Results from this study revealed that, the expression of subolesin was significantly higher in salivary glands of infected R. microplus in comparison to uninfected ones.

Asunto(s)

Anaplasma marginale/fisiología , Antígenos/genética , Proteínas de Artrópodos/genética , Expresión Génica , Rhipicephalus/genética , Rhipicephalus/microbiología , Anaplasmosis/inmunología , Anaplasmosis/microbiología , Animales , Antígenos/metabolismo , Proteínas de Artrópodos/metabolismo , Bovinos , Enfermedades de los Bovinos/inmunología , Enfermedades de los Bovinos/microbiología , Femenino , Reacción en Cadena de la Polimerasa/veterinaria , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Rhipicephalus/metabolismo , Glándulas Salivales/metabolismo , Glándulas Salivales/microbiología

RESUMEN

Water buffalo (Bubalus bubalis) is a potential reservoir for Anaplasma marginale in livestock ecosystems of tropical countries. However, their participation in the epidemiological process of bovine anaplasmosis in endemic areas remains unclear. In the present study, the reservoir competence of water buffalo for A. marginale was explored by focusing on the analysis of rickettsemia levels in carrier animals, and the genetic characterization of A. marginale strains from cattle and buffalo. Eight groups of cattle and water buffaloes were randomly selected from cohabiting herds in four livestock ecosystems of Cuba, together with two control groups from unrelated cattle and buffalo herds. A total of 180 adult animals (88 water buffalo and 92 cattle) were sampled. Rickettsemia in carrier animals was determined by quantitative real-time PCR. The rickettsemia (parasitemia) levels in cattle were higher than in buffaloes, however the rickettsemia in buffalo may be enough to infect R. microplus ticks. The genetic diversity of A. marginale was assessed by strain characterization and phylogenetic analysis of 27 msp1α gene sequences. The results showed genetic similarity among strains from cattle and water buffalo, suggesting the occurrence of cross-species transmission.

Asunto(s)

Anaplasma marginale/genética , Anaplasmosis/epidemiología , Búfalos/microbiología , Enfermedades de los Bovinos/epidemiología , Reservorios de Enfermedades/veterinaria , Anaplasmosis/transmisión , Animales , Proteínas de la Membrana Bacteriana Externa/genética , Bovinos/microbiología , Enfermedades de los Bovinos/microbiología , Enfermedades de los Bovinos/transmisión , Estudios de Cohortes , Cuba/epidemiología , Reservorios de Enfermedades/microbiología , Variación Genética , Filogenia , Reacción en Cadena en Tiempo Real de la Polimerasa , Garrapatas/microbiología

RESUMEN

The objective of this study was to screen and identify rickettsial organisms in ectoparasites collected from dogs in a shelter in Gomez Palacio, Durango, Mexico. One hundred dogs were inspected for ectoparasites. All the dogs were parasitized with Rhipicephalus sanguineus ticks, three with Heterodoxus spiniger lice and one with Ctenocephalides felis fleas. DNA was extracted from the ectoparasites found on each dog, and PCR with the primers for the Anaplasmataceae 16S rRNA and citrate synthase gltA genes were performed. Eight DNA samples obtained from ticks, three from lice and one from fleas were positive to 16S rRNA. Only one sample from C. felis and one from H. spiniger were positive to gltA. Sequence analysis of amplified products from C. felis showed identity to Rickettsia felis, Wolbachia pipientis, and Wolbachia spp., while a sequence from H. spiniger showed identity to Wolbachia spp. Herein we report the molecular detection of R. felis, W. pipientis, and Wolbachia spp. in C. felis and H. spiniger in northern Mexico. These results contribute to the knowledge of the microorganisms present in ectoparasites from dogs in Mexico.

Asunto(s)

ADN Bacteriano/genética , Enfermedades de los Perros/parasitología , Infestaciones Ectoparasitarias/veterinaria , Rickettsia/genética , Animales , Secuencia de Bases , Enfermedades de los Perros/epidemiología , Perros , Infestaciones Ectoparasitarias/epidemiología , Infestaciones Ectoparasitarias/parasitología , Vivienda para Animales , Phthiraptera/microbiología , Filogenia , Reacción en Cadena de la Polimerasa , ARN Bacteriano/genética , ARN Ribosómico 16S/genética , Rickettsia/aislamiento & purificación , Siphonaptera/microbiología , Especificidad de la Especie , Garrapatas/microbiología

RESUMEN

The tick-borne pathogens Ehrlichia canis and Anaplasma platys are the causative agents of canine monocytic ehrlichiosis (CME) and canine cyclic thrombocytopenia (CCT). Although molecular evidence of E. canis has been shown, phylogenetic analysis of this pathogen has not been performed and A. platys has not been identified in Mexico, where the tick vector Rhipicephalus sanguineus sensu lato (s.l.) is common. The aim of this research was to screen, identify and characterize E. canis and A. platys by PCR and phylogenetic analysis in dogs from La Comarca Lagunera, a region formed by three municipalities, Torreon, Gomez-Palacio and Lerdo, in the Northern states of Coahuila and Durango, Mexico. Blood samples and five engorged R. sanguineus s.l. ticks per animal were collected from 43 females and 57 male dogs presented to veterinary clinics or lived in the dog shelter from La Comarca Lagunera. All the sampled dogs were apparently healthy and PCR for Anaplasma 16S rRNA, Ehrlichia 16S rRNA, and E. canis trp36 were performed. PCR products were sequenced and used for phylogenetic analysis. PCR products were successfully amplified in 31% of the samples using primers for Anaplasma 16S rRNA, while 10% and 4% amplified products using primers for Ehrlichia 16S rRNA and E. canis trp36 respectively. Subsequent sequencing and phylogenetic analyses of these products showed that three samples corresponded to A. platys and four to E. canis. Based on the analysis of trp36 we confirmed that the E. canis strains isolated from Mexico belong to a conservative clade of E. canis and are closely related to strains from USA. In conclusion, this is the first molecular identification of A. platys and the first molecular characterization and phylogenetic study of both A. platys and E. canis in dogs in Mexico.

Asunto(s)

Anaplasma/aislamiento & purificación , Anaplasmosis/microbiología , Enfermedades de los Perros/microbiología , Ehrlichia canis/aislamiento & purificación , Ehrlichiosis/veterinaria , Anaplasma/genética , Anaplasmosis/epidemiología , Animales , Vectores Arácnidos/microbiología , Enfermedades de los Perros/epidemiología , Perros , Ehrlichia canis/genética , Ehrlichiosis/epidemiología , Ehrlichiosis/microbiología , Femenino , Masculino , México/epidemiología , Filogenia , ARN Ribosómico 16S/genética , Rhipicephalus sanguineus/microbiología , Análisis de Secuencia de ADN/veterinaria

RESUMEN

BACKGROUND: In rural parts of Africa, dogs live in close association with humans and livestock, roam freely, and usually do not receive prophylactic measures. Thus, they are a source of infectious disease for humans and for wildlife such as protected carnivores. In 2011, an epidemiological study was carried out around three conservation areas in Uganda to detect the presence and determine the prevalence of vector-borne pathogens in rural dogs and associated ticks to evaluate the risk that these pathogens pose to humans and wildlife. METHODS: Serum samples (n = 105), blood smears (n = 43) and blood preserved on FTA cards (n = 38) and ticks (58 monospecific pools of Haemaphysalis leachi and Rhipicephalus praetextatus including 312 ticks from 52 dogs) were collected from dogs. Dog sera were tested by indirect immunofluorescence to detect the presence of antibodies against Rickettsia conorii and Ehrlichia canis. Antibodies against R. conorii were also examined by indirect enzyme immunoassay. Real time PCR for the detection of Rickettsia spp., Anaplasmataceae, Bartonella spp. and Babesia spp. was performed in DNA extracted from FTA cards and ticks. RESULTS: 99% of the dogs were seropositive to Rickettsia spp. and 29.5% to Ehrlichia spp. Molecular analyses revealed that 7.8% of the blood samples were infected with Babesia rossi, and all were negative for Rickettsia spp. and Ehrlichia spp. Ticks were infected with Rickettsia sp. (18.9%), including R. conorii and R. massiliae; Ehrlichia sp. (18.9%), including E. chaffeensis and Anaplasma platys; and B. rossi (1.7%). Bartonella spp. was not detected in any of the blood or tick samples. CONCLUSIONS: This study confirms the presence of previously undetected vector-borne pathogens of humans and animals in East Africa. We recommend that dog owners in rural Uganda be advised to protect their animals against ectoparasites to prevent the transmission of pathogens to humans and wildlife.

Asunto(s)

Enfermedades de los Perros/epidemiología , Ixodidae , Infestaciones por Garrapatas/epidemiología , Enfermedades por Picaduras de Garrapatas/epidemiología , Anaplasma/genética , Anaplasma/aislamiento & purificación , Animales , Babesia/genética , Babesia/aislamiento & purificación , Bartonella/genética , Bartonella/aislamiento & purificación , Secuencia de Bases , Enfermedades de los Perros/microbiología , Enfermedades de los Perros/parasitología , Perros , Ehrlichia/inmunología , Ehrlichia/aislamiento & purificación , Femenino , Humanos , Ixodidae/microbiología , Ixodidae/parasitología , Masculino , Datos de Secuencia Molecular , Prevalencia , Rickettsia/inmunología , Rickettsia/aislamiento & purificación , Infestaciones por Garrapatas/parasitología , Infestaciones por Garrapatas/prevención & control , Enfermedades por Picaduras de Garrapatas/microbiología , Enfermedades por Picaduras de Garrapatas/parasitología , Uganda/epidemiología

RESUMEN

Anaplasma marginale is an economically important tick-borne pathogen of cattle that causes bovine anaplasmosis. A wide range of geographic strains of A. marginale have been isolated from cattle, several of which have been characterized using genomics and proteomics. While many of these strains have been propagated in tick lines, comparative analyses after propagation in tick cells have not been reported. The overall purpose of this research therefore was to compare the degree of conservation of selected genes after propagation in tick cell culture among A. marginale strains from the U.S. (the Virginia strain) and Brazil (UFMG1 and UFMG2 strains). The genes studied herein included those which encode the proteins HSP70 and SODB involved in heat shock and stress responses, respectively, and two genes that encode major surface proteins MSP4 and MSP5. Strain identities were first confirmed by sequencing the tandem repeats of the msp1a gene which encodes for the adhesin, MSP1a. The results of these studies demonstrated that the genes encoding for both stress response and heat shock proteins were highly conserved among the three A. marginale strains. Antibodies specific for MSP4, MSP5, SODB and HSP70 proteins were used to further characterize the A. marginale strains, and they reacted with all of these strains propagated in tick cell culture, providing further evidence for antigenic conservation. Although antigenic differences were not found among the three A. marginale strains, multi-locus sequence analysis (MLSA) performed with nucleotide sequences of these genes demonstrated that the A. marginale Brazilian and U.S. strains fall in different clades. These results showed that phylogenetically distant strains of A. marginale are antigenically conserved, even after several in vitro passages, supporting the use of some of the above conserved proteins as candidates for universal vaccines.

Asunto(s)

Anaplasma marginale/aislamiento & purificación , Anaplasmosis/inmunología , Vectores Arácnidos/microbiología , Proteínas Bacterianas/genética , Proteínas Bacterianas/inmunología , Enfermedades de los Bovinos/inmunología , Garrapatas/microbiología , Anaplasma marginale/clasificación , Anaplasma marginale/genética , Anaplasma marginale/crecimiento & desarrollo , Anaplasmosis/microbiología , Animales , Variación Antigénica , Brasil , Bovinos , Enfermedades de los Bovinos/microbiología , Secuencia Conservada , Datos de Secuencia Molecular , Filogenia , Estados Unidos

RESUMEN

Anaplasma marginale is the most prevalent pathogen of cattle in tropical and subtropical regions of the world and causes the disease bovine anaplasmosis. The importance of water buffalo in the world economy is increasing. In addition, while water buffalo may serve as a reservoir host for A. marginale, the susceptibility of this host for A. marginale cattle strains in Brazil has not been reported. The major surface protein 1 alpha (msp1α) gene has been shown to be a stable genetic marker for identification of A. marginale strains. Herein, we analyzed blood samples from 200 water buffalo and identified the A. marginale strains in an endemic area of Rio de Janeiro, Brazil, where ticks were present and water buffalo and cattle co-mingled. Ticks that were feeding on the study buffalo were collected and identified. The prevalence of A. marginale in water buffalo in this study was low (10%). Sequence analysis of the msp1α gene demonstrated the presence of 8 different A. marginale strains. Two A. marginale strains in the water buffalo, (α-ß-ß-ß-Γ) and (α-ß-ß-Γ), were similar to those reported in cattle from nearby regions. The results of this study suggested that water buffalo in this region are naturally infected with the same strains of A. marginale found in cattle.

Asunto(s)

Anaplasma marginale/aislamiento & purificación , Anaplasmosis/epidemiología , Búfalos/microbiología , Enfermedades de los Bovinos/epidemiología , Garrapatas/microbiología , Secuencia de Aminoácidos , Anaplasma marginale/genética , Anaplasmosis/microbiología , Animales , Proteínas de la Membrana Bacteriana Externa/genética , Brasil/epidemiología , Bovinos , Enfermedades de los Bovinos/microbiología , Reservorios de Enfermedades/microbiología , Marcadores Genéticos/genética , Genotipo , Datos de Secuencia Molecular , Filogenia , Análisis de Secuencia de ADN

RESUMEN

The rickettsia Anaplasma marginale is the etiologic agent of bovine anaplasmosis, an important tick-borne disease affecting cattle in tropical and subtropical regions of the world. In endemic regions, the genetic diversity of this pathogen is usually related to the high prevalence of the disease in cattle. The major surface protein 1 alpha (MSP1a) has been used as a marker to characterize the genetic diversity and for geographical identification of A. marginale strains. The present study reports the characterization of A. marginale MSP1a diversity in water buffaloes. Blood samples were collected from 200 water buffaloes on Marajó Island, Brazil where the largest buffalo herd is located in the Western hemisphere. Fifteen buffaloes (7.5%) were positive for A. marginale msp1α by PCR. Four different strains of A. marginale with MSP1a tandem repeat structures (4-63-27), (162-63-27), (78-24-24-25-31) and (τ-10-10-15) were found, being (4-63-27) the most common. MSP1a tandem repeats composition in buffalos and phylogenetic analysis using msp1α gene showed that the A. marginale strains identified in buffaloes are closely related to A. marginale strains from cattle. The results demonstrated low genetic diversity of A. marginale associated with low bacterial prevalence in buffaloes and suggested that buffaloes may be reservoirs of this pathogen for cattle living in the same area. The results also suggested that mechanical transmission and not biological transmission by ticks might be playing the major role for pathogen circulation among water buffaloes in Marajó Island, Brazil.

Asunto(s)

Anaplasma marginale/genética , Anaplasmosis/epidemiología , Vectores Arácnidos/microbiología , Enfermedades de los Bovinos/epidemiología , Variación Genética , Enfermedades por Picaduras de Garrapatas/veterinaria , Garrapatas/microbiología , Secuencia de Aminoácidos , Anaplasma marginale/aislamiento & purificación , Animales , Secuencia de Bases , Brasil , Búfalos , Bovinos , Enfermedades de los Bovinos/microbiología , ADN Bacteriano/química , ADN Bacteriano/genética , Femenino , Datos de Secuencia Molecular , Filogenia , Prevalencia , Alineación de Secuencia/veterinaria , Análisis de Secuencia de ADN/veterinaria , Enfermedades por Picaduras de Garrapatas/epidemiología , Enfermedades por Picaduras de Garrapatas/microbiología

RESUMEN

Cattle ticks are distributed worldwide and affect animal health and livestock production. White tailed deer (WTD) sustain and spread cattle tick populations. The aim of this study was to model the efficacy of anti-tick vaccination of WTD to control tick infestations in the absence of cattle vaccination in a territory where both host species coexist and sustain cattle tick populations. Agent-based models that included land cover/landscape properties (patch size, distances to patches) and climatic conditions were built in a GIS environment to simulate WTD vaccine effectiveness under conditions where unvaccinated cattle shared the landscape. Published and validated information on tick life cycle was used to build models describing tick mortality and developmental rates. Data from simulations were applied to a large territory in northeastern Mexico where cattle ticks are endemic and WTD and cattle share substantial portions of the habitat. WTD movements were simulated together with tick population dynamics considering the actual landscape and climatic features. The size of the vegetation patches and the distance between patches were critical for the successful control of tick infestations after WTD vaccination. The presence of well-connected, large vegetation patches proved essential for tick control, since the tick could persist in areas of highly fragmented habitat. The continued application of one yearly vaccination on days 1-70 for three years reduced tick abundance/animal/patch by a factor of 40 and 60 for R. annulatus and R. microplus, respectively when compared to non-vaccinated controls. The study showed that vaccination of WTD alone during three consecutive years could result in the reduction of cattle tick populations in northeastern Mexico. Furthermore, the results of the simulations suggested the possibility of using vaccines to prevent the spread and thus the re-introduction of cattle ticks into tick-free areas.

Asunto(s)

Enfermedades de los Bovinos/prevención & control , Clima , Ciervos , Control de Ácaros y Garrapatas/métodos , Infestaciones por Garrapatas/veterinaria , Vacunación/veterinaria , Animales , Bovinos , México , Modelos Teóricos , Rhipicephalus , Infestaciones por Garrapatas/prevención & control

RESUMEN

The ovine brucellosis caused by Brucella ovis has tropism for reproductive tissues but until now the mechanism of bacterial persistence is not understood. Cytokine expression profiles were studied for 8 months in rams after being experimentally infected with the rough virulent strain of B. ovis (R-B. ovis) to study the pathogenesis of B. ovis and immune mechanism possibly associated to bacteria tropism and persistence. The messenger RNA (mRNA) expression levels of interleukin-1α (IL-1α), IL-1ß, IL-6, IL-10, IL-12, interferon-γ (INF-γ) and tumour necrosis factor-α (TNF-α) cytokines were quantified by real-time quantitative RT-PCR (qRT-PCR) in reproductive tissues (epididymus, testicles, ampolae, vesicular glands and bulbourethral glands), and non-reproductive (liver, spleen and kidneys) tissues at 30, 60, 120 and 240 days post infection (dpi). During the acute phase of infection at 30 dpi, the host immune response was most notable demonstrating an up-regulation of several cytokines in reproductive tissues, including the epididymus (IL-6, IL-1ß and IL-1α), testicles (INF-γ and IL-12), bulbourethral glands (IL-6 and TNF-α) and ampolae (INF-γ, IL-10, IL-1ß and IL-1α). During the development of infection, cytokine gene expression levels decreased, providing evidence of immunosuppression and evidence of immune evasion that favoured persistence of chronic R-B. ovis infection. During the chronic phase of R-B. ovis infection (120 and 240 dpi), cytokine production was down-regulated in the epididymus (IL-1ß and IL-1α), testicles (INF-γ and IL-12), and ampolae (INF-γ, IL-10, IL-1ß and IL-1α), with the exception of the bulbourethral glands (IL-6 and TNF-α) and epididymus (IL-6); in these tissues, R-B. ovis infection resulted in up-regulation of the pro-inflammatory cytokine IL-6. Herein, we report cytokine expression profiles in tissues of rams experimentally infected with the rough strain of B. ovis, which are associated with bacterial persistence and macrophage activation.

Asunto(s)

Brucella ovis/patogenicidad , Brucelosis/veterinaria , Citocinas/biosíntesis , Genitales Masculinos/inmunología , Genitales Masculinos/microbiología , Enfermedades de las Ovejas/microbiología , Animales , Brucella ovis/genética , Brucella ovis/inmunología , Brucelosis/genética , Brucelosis/inmunología , Citocinas/genética , Citocinas/inmunología , Inflamación/genética , Inflamación/inmunología , Inflamación/microbiología , Activación de Macrófagos , Masculino , ARN Mensajero/genética , ARN Mensajero/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Ovinos , Enfermedades de las Ovejas/genética , Enfermedades de las Ovejas/inmunología , Regulación hacia Arriba

Asunto(s)

Brucelosis/veterinaria , Ciervos , Hepatitis E/veterinaria , Paratuberculosis/epidemiología , Zoonosis , Animales , Anticuerpos Antibacterianos/sangre , Brucella/inmunología , Brucelosis/epidemiología , Brucelosis/inmunología , Ciervos/microbiología , Ciervos/virología , Anticuerpos Antihepatitis/sangre , Hepatitis E/epidemiología , Hepatitis E/inmunología , Virus de la Hepatitis E/inmunología , México/epidemiología , Paratuberculosis/microbiología , Prevalencia , Tuberculina/inmunología , Zoonosis/epidemiología , Zoonosis/microbiología , Zoonosis/virología

RESUMEN

The horn fly Haematobia irritans (Linnaeus, 1758) (Diptera: Muscidae) is one of the most important ectoparasites of cattle. The parasitism of horn flies interferes with cattle feeding, thus reducing weight gain and milk production. Additionally, horn flies are mechanical vectors of pathogens that cause disease in cattle. The aims of this study were to identify microorganisms in partially fed female horn flies through mining of expressed sequence tags (ESTs) and to characterize microorganism prevalence using real-time RT-PCR. Seven unigenes containing 24 ESTs were homologous to infectious agents. Microorganisms identified in partially fed female horn flies ESTs included Nora virus (3 unigenes; 8 ESTs), Wolbachia endosymbionts (3 unigenes; 3 ESTs), and Mycobacterium bovis (1 unigene; 13 ESTs). These results expanded the repertoire of microorganisms that could cause persistent infections or be mechanically transmitted by horn flies and support further studies on the role of horn flies in the epidemiology of these pathogens in Mexico.

Asunto(s)

Dípteros/microbiología , Dípteros/fisiología , Mycobacterium bovis/aislamiento & purificación , Picornaviridae/aislamiento & purificación , Wolbachia/aislamiento & purificación , Animales , Bovinos/sangre , Etiquetas de Secuencia Expresada , Femenino , Mycobacterium bovis/clasificación , Mycobacterium bovis/genética , Picornaviridae/clasificación , Picornaviridae/genética , ADN Polimerasa Dirigida por ARN , Reacción en Cadena en Tiempo Real de la Polimerasa , Wolbachia/clasificación , Wolbachia/genética

RESUMEN

The recombinant Bm86-based tick vaccines have shown their efficacy for the control of cattle ticks, Rhipicephalus (Boophilus) microplus and R. annulatus infestations. However, cattle ticks often co-exist with multi-host ticks such as Hyalomma and Amblyomma species, thus requiring the control of multiple tick infestations for cattle and other hosts. Vaccination trials using a R. microplus recombinant Bm86-based vaccine were conducted in cattle and camels against Hyalomma dromedarii and in cattle against Amblyomma cajennense immature and adult ticks. The results showed an 89% reduction in the number of H. dromedarii nymphs engorging on vaccinated cattle, and a further 32% reduction in the weight of the surviving adult ticks. In vaccinated camels, a reduction of 27% and 31% of tick engorgement and egg mass weight, respectively was shown, while egg hatching was reduced by 39%. However, cattle vaccination with Bm86 did not have an effect on A. cajennense tick infestations. These results showed that Bm86 vaccines are effective against R. microplus and other tick species but improved vaccines containing new antigens are required to control multiple tick infestations.

Asunto(s)

Enfermedades de los Bovinos/prevención & control , Ixodidae/inmunología , Ixodidae/patogenicidad , Glicoproteínas de Membrana/inmunología , Proteínas Recombinantes/inmunología , Infestaciones por Garrapatas/veterinaria , Vacunas/inmunología , Animales , Camelus , Bovinos , Enfermedades de los Bovinos/inmunología , Femenino , Masculino , Glicoproteínas de Membrana/administración & dosificación , Proteínas Recombinantes/administración & dosificación , Infestaciones por Garrapatas/inmunología , Infestaciones por Garrapatas/prevención & control , Vacunas/administración & dosificación , Vacunas Sintéticas/administración & dosificación , Vacunas Sintéticas/inmunología

RESUMEN

Red deer (Cervus elaphus) and white-tailed deer (Odocoileus virginianus) are hosts for different tick species and tick-borne pathogens and play a role in tick dispersal and maintenance in some regions. These factors stress the importance of controlling tick infestations in deer and several methods such as culling and acaricide treatment have been used. Tick vaccines are a cost-effective alternative for tick control that reduced cattle tick infestations and tick-borne pathogens prevalence while reducing the use of acaricides. Our hypothesis is that vaccination with vector protective antigens can be used for the control of tick infestations in deer. Herein, three experiments were conducted to characterize (1) the antibody response in red deer immunized with recombinant BM86, the antigen included in commercial tick vaccines, (2) the antibody response and control of cattle tick infestations in white-tailed deer immunized with recombinant BM86 or tick subolesin (SUB) and experimentally infested with Rhipicephalus (Boophilus) microplus, and (3) the antibody response and control of Hyalomma spp. and Rhipicephalus spp. field tick infestations in red deer immunized with mosquito akirin (AKR), the SUB ortholog and candidate protective antigen against different tick species and other ectoparasites. The results showed that deer produced an antibody response that correlated with the reduction in tick infestations and was similar to other hosts vaccinated previously with these antigens. The overall vaccine efficacy was similar between BM86 (E=76%) and SUB (E=83%) for the control of R. microplus infestations in white-tailed deer. The field trial in red deer showed a 25-33% (18-40% when only infested deer were considered) reduction in tick infestations, 14-20 weeks after the first immunization. These results demonstrated that vaccination with vector protective antigens could be used as an alternative method for the control of tick infestations in deer to reduce tick populations and dispersal in regions where deer are relevant hosts for these ectoparasites.

Asunto(s)

Antígenos/inmunología , Proteínas de Artrópodos/inmunología , Proteínas de Insectos/inmunología , Ixodes/inmunología , Glicoproteínas de Membrana/inmunología , Proteínas Recombinantes/inmunología , Infestaciones por Garrapatas/veterinaria , Vacunación/métodos , Vacunas/inmunología , Animales , Antígenos/administración & dosificación , Proteínas de Artrópodos/administración & dosificación , Ciervos , Femenino , Proteínas de Insectos/administración & dosificación , Masculino , Glicoproteínas de Membrana/administración & dosificación , Proteínas Recombinantes/administración & dosificación , Infestaciones por Garrapatas/prevención & control , Vacunas/administración & dosificación

RESUMEN

Vaccines containing the Rhipicephalus (Boophilus) microplus BM86 and BM95 antigens protect cattle against tick infestations. Tick subolesin (SUB), elongation factor 1a (EF1a) and ubiquitin (UBQ) are new candidate protective antigens for the control of cattle tick infestations. Previous studies showed that R. microplus BM95 immunogenic peptides fused to the Anaplasma marginale major surface protein (MSP) 1a N-terminal region (BM95-MSP1a) for presentation on the Escherichia coli membrane were protective against R. microplus infestations in rabbits. In this study, we extended these results by expressing SUB-MSP1a, EF1a-MSP1a and UBQ-MSP1a fusion proteins on the E. coli membrane using this system and demonstrating that bacterial membranes containing the chimeric proteins BM95-MSP1a and SUB-MSP1a were protective (>60% vaccine efficacy) against experimental R. microplus and Rhipicephalus annulatus infestations in cattle. This system provides a novel, simple and cost-effective approach for the production of tick protective antigens by surface display of antigenic protein chimera on the E. coli membrane and demonstrates the possibility of using recombinant bacterial membrane fractions in vaccine preparations to protect cattle against tick infestations.

Asunto(s)

Vacunas Bacterianas/inmunología , Enfermedades de los Bovinos/prevención & control , Proteínas de Insectos/inmunología , Glicoproteínas de Membrana/inmunología , Rhipicephalus/inmunología , Infestaciones por Garrapatas/veterinaria , Animales , Vacunas Bacterianas/administración & dosificación , Bovinos , Enfermedades de los Bovinos/inmunología , Enfermedades de los Bovinos/parasitología , Membrana Celular/genética , Membrana Celular/inmunología , Escherichia coli/genética , Escherichia coli/inmunología , Proteínas de Insectos/genética , Glicoproteínas de Membrana/genética , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/inmunología , Infestaciones por Garrapatas/parasitología , Infestaciones por Garrapatas/prevención & control , Vacunas Sintéticas/administración & dosificación , Vacunas Sintéticas/inmunología

RESUMEN

BACKGROUND: The horn fly, Haematobia irritans (Linnaeus, 1758) (Diptera: Muscidae) is one of the most important ectoparasites of pastured cattle. Horn flies infestations reduce cattle weight gain and milk production. Additionally, horn flies are mechanical vectors of different pathogens that cause disease in cattle. The aim of this study was to conduct a functional genomics study in female horn flies using Expressed Sequence Tags (EST) analysis and RNA interference (RNAi). RESULTS: A cDNA library was made from whole abdominal tissues collected from partially fed adult female horn flies. High quality horn fly ESTs (2,160) were sequenced and assembled into 992 unigenes (178 contigs and 814 singlets) representing molecular functions such as serine proteases, cell metabolism, mitochondrial function, transcription and translation, transport, chromatin structure, vitellogenesis, cytoskeleton, DNA replication, cell response to stress and infection, cell proliferation and cell-cell interactions, intracellular trafficking and secretion, and development. Functional analyses were conducted using RNAi for the first time in horn flies. Gene knockdown by RNAi resulted in higher horn fly mortality (protease inhibitor functional group), reduced oviposition (vitellogenin, ferritin and vATPase groups) or both (immune response and 5'-NUC groups) when compared to controls. Silencing of ubiquitination ESTs did not affect horn fly mortality and oviposition while gene knockdown in the ferritin and vATPse functional groups reduced mortality when compared to controls. CONCLUSIONS: These results advanced the molecular characterization of this important ectoparasite and suggested candidate protective antigens for the development of vaccines for the control of horn fly infestations.

Asunto(s)

Genoma de los Insectos , Genómica , Muscidae/genética , Animales , Etiquetas de Secuencia Expresada , Femenino , Biblioteca de Genes , Interferencia de ARN , Análisis de Secuencia de ADN

RESUMEN

Tick subolesin was shown in immunization trials using the recombinant protein to protect hosts against tick infestations. In this study, we demonstrated that subolesin vaccination and release of ticks after subolesin knockdown by RNA interference (RNAi) could be used for the control of Rhipicephalus (Boophilus) microplus tick infestations in cattle and suggested that the combination of these methods could increase the efficacy of cattle tick control under some circumstances. The greatest tick control was obtained when both release of ticks after subolesin knockdown and vaccination were used concurrently. However, modeling results suggested that vaccine efficacy could be increased if at least 80% of the ticks infesting cattle correspond to subolesin-knockdown ticks. The results of this proof-of-concept trial demonstrated the efficacy of the sterile acarine technique (SAT) through production of subolesin-knockdown larvae by dsRNA injection into replete females for the control of R. microplus tick infestations, alone or in combination with subolesin vaccination.

Asunto(s)

Antígenos/inmunología , Rhipicephalus/genética , Control de Ácaros y Garrapatas/métodos , Infestaciones por Garrapatas/veterinaria , Vacunación , Animales , Formación de Anticuerpos , Antígenos/genética , Proteínas de Artrópodos , Bovinos , Femenino , Técnicas de Silenciamiento del Gen , Interferencia de ARN , Infestaciones por Garrapatas/prevención & control , Vacunación/veterinaria , Vacunas/genética , Vacunas/inmunología

RESUMEN

The cattle ticks, Rhipicephalus (Boophilus) spp., affect cattle production in tropical and subtropical regions of the world. Tick vaccines constitute a cost-effective and environmentally friendly alternative to tick control. The recombinant Rhipicephalus microplus Bm86 antigen has been shown to protect cattle against tick infestations. However, variable efficacy of Bm86-based vaccines against geographic tick strains has encouraged the research for additional tick-protective antigens. Herein, we describe the analysis of R. microplus glutathione-S transferase, ubiquitin (UBQ), selenoprotein W, elongation factor-1 alpha, and subolesin (SUB) complementary DNAs (cDNAs) by RNA interference (RNAi) in R. microplus and Rhipicephalus annulatus. Candidate protective antigens were selected for vaccination experiments based on the effect of gene knockdown on tick mortality, feeding, and fertility. Two cDNA clones encoding for UBQ and SUB were used for cattle vaccination and infestation with R. microplus and R. annulatus. Control groups were immunized with recombinant Bm86 or adjuvant/saline. The highest vaccine efficacy for the control of tick infestations was obtained for Bm86. Although with low immunogenic response, the results with the SUB vaccine encourage further investigations on the use of recombinant subolesin alone or in combination with other antigens for the control of cattle tick infestations. The UBQ peptide showed low immunogenicity, and the results of the vaccination trial were inconclusive to assess the protective efficacy of this antigen. These experiments showed that RNAi could be used for the selection of candidate tick-protective antigens. However, vaccination trials are necessary to evaluate the effect of recombinant antigens in the control of tick infestations, a process that requires efficient recombinant protein production and formulation systems.

Asunto(s)

Proteínas de Insectos/inmunología , Rhipicephalus/inmunología , Infestaciones por Garrapatas/prevención & control , Vacunación , Animales , Bovinos , Conducta Alimentaria , Femenino , Fertilidad , Técnicas de Silenciamiento del Gen , Proteínas de Insectos/genética , Datos de Secuencia Molecular , Rhipicephalus/genética , Análisis de Secuencia de ADN , Análisis de Supervivencia , Infestaciones por Garrapatas/inmunología