Emerging Tickborne Bacteria in Cattle from Colombia.

Ehrlichia minasensis is a new pathogenic bacterial species that infects cattle, and Borrelia theileri causes bovine borreliosis. We detected E. minasensis and B. theileri DNA in cattle from southwestern Colombia by using PCR. E. minasensis and B. theileri should be considered potential etiologies of febrile syndrome in cattle from Colombia.

Amblyomma mixtum free-living stages: Inferences on dry and wet seasons use, preference, and niche width in an agroecosystem (Yopal, Casanare, Colombia).

The formulation of effective control strategies for any pest species generally involves the study of habitat use and preference and niche width in anthropogenically transformed natural landscapes. We evaluated whether the use, habitat preference, and niche range of the Amblyomma mixtum tick changed between stages, habitats, and seasonality (dry-wet seasons 2019) on a farm in Yopal (Casanare, Colombia). The presence and relative abundance of free-living larvae, nymphs, and adults was quantified in four different habitats according to the type of vegetation cover (Riparian Forest, Cocoa Crop, King Grass Crop, and Star Grass Paddock). Habitat availability was estimated, environmental variables were analyzed, and various indices of habitat use and preference, and niche width were calculated. A. mixtum's habitat use and preference, and niche width changed between stages, habitat types, and time of the year. The total abundance of A. mixtum was an order of magnitude greater in the dry season than the wet season. In the dry season, all stages used all habitats, while A. mixtum adults used all the habitats in both seasons. In the dry season, nymphs and larvae preferred three out of the four habitats, while adults preferred the King Grass Crop. In the wet season, nymphs and larvae preferred two habitats, whereas the adults preferred the King Grass Crop. The value of the niche width index was high for larvae, nymphs, and adults in the dry season, while it was high only for adults in the wet season. Thus, A. mixtum's vast environmental tolerance and niche breadth allows the species to use and colonize changing habitats (unstable or temporary) with fluctuating environmental conditions (e.g., King Grass Crop), potentially keeping a stable population over time and making it an extremely resistant species. However, the wet flooding season in Yopal may exceed A. mixtum's stages' tolerances.

Experimental infection and vector competence of Amblyomma patinoi, a member of the Amblyomma cajennense species complex, for the human pathogen Rickettsia rickettsii.

Amblyomma patinoi ticks infected with Rickettsia rickettsii are present in Colombia, but its vector competence is unknown. Hence, we evaluated the vector competence of A. patinoi with R. rickettsii under laboratory conditions. Experimental guinea pigs and rabbits (males and females) were separated in the infected group (IG) and the control group (CG). In the IG, the filial 1 (F1) larvae (R. rickettsii-free) from Colombian A. patinoi engorged female specimens were exposed to R. rickettsii (ITU strain) by feeding on infected guinea pigs. Next, F1 nymphs and adults, and F2 larvae were allowed to feed on uninfected guinea pigs or rabbits and tested by qPCR targeting the gltA rickettsial gene. All animals used to feed the IG F1 ticks became febrile and had R. rickettsii infection (89% fatality rate) detected through serological or molecular techniques. After the F1 larvae ticks became R. rickettsii infected, subsequent IG tick stages were able to maintain the rickettsial infection by transstadial maintenance to all infested animals, indicating A. patinoi vector competence. Subsequently, almost 31% of the F1 female egg masses and only 42% of their F2 larvae were infected. Less than 50% of the infected females transmitted R. rickettsii transovarially, and only a part of the offspring were infected. This study demonstrated that A. patinoi might not be able to sustain R. rickettsii infection by transovarial transmission for successive tick generations without horizontal transmission via rickettsemic hosts. This condition might result in low R. rickettsii-infection rates of A. patinoi under natural conditions.

Seroprevalence and Genotypic Analysis of Ehrlichia canis Infection in Dogs and Humans in Cauca, Colombia.

Ehrlichia canis infections have been reported in humans in Venezuela and Costa Rica. In this study, 506 healthy residents and 114 dogs from four municipalities (Cauca, Colombia) were surveyed and blood samples collected. Antibodies to E. canis in human and canine sera were evaluated using the Tandem repeat protein 19 (TRP19) peptide ELISA and indirect immunofluorescence assay (IFA). Ehrlichia canis TRP19 antibodies were detected in only 1/506 human sera, but the single positive sample was negative by IFA. The majority (75/114; 66%) of dogs surveyed had antibodies to the E. canis TRP19 peptide by ELISA, and eight randomly selected sera were further confirmed by E. canis IFA. Genomic DNA samples obtained from 73 E. canis TRP19 ELISA-positive dog blood samples were examined by PCR targeting the 16S ribosomal ribonucleic acid (rRNA) gene. Ehrlichia canis 16S rRNA was amplified in 30 (41%) of the dogs, and 16 amplicons were selected for DNA sequencing, which confirmed that all were E. canis. A second PCR was performed on the 16 confirmed E. canis 16S rRNA PCR-positive samples to determine the TRP36 genotype by amplifying the trp36 gene. TRP36 PCR amplicon sequencing identified nine dogs infected with the U.S. E. canis TRP36 genotype (56%), one dog with the Brazilian genotype (6%), and six dogs with the Costa Rican genotype (38%). Moreover, these molecular genotype signatures were consistent with serologic analysis using TRP36 genotype-specific peptides. Notably, there was no serologic evidence of E. canis infection in humans, suggesting that E. canis infection in dogs in Cauca is not associated with zoonotic human infection.

Epidemiology of Spotted Fever Group Rickettsioses and Acute Undifferentiated Febrile Illness in Villeta, Colombia.

Etiology of acute undifferentiated febrile syndrome (AUFS) is often unknown, leading to inaccurate diagnosis and treatment. Villeta town has been identified as an endemic area for spotted fever group (SFG) rickettsioses but little is known about possible amplifier hosts and other Rickettsia species different from Rickettsia rickettsii. Besides, few studies have approached other AUFS etiologies in the region. We investigated the role of dengue, leptospirosis, rickettsioses, human anaplasmosis, and Q fever as possible causes of AUFS in patients from Villeta. Sera specimens and ticks from animals as well as ticks from vegetation were studied for the presence of different Rickettsia spp. Among 104 sera from patients with AUFS, 16.4%, 24.0%, and 2.9% patients seroconverted to dengue, Leptospira, and SFG Rickettsia, respectively, with a case of probable coinfection or cross-reaction with Anaplasma phagocytophilum. None of the samples were reactive for Coxiella burnetii. Sera samples from 74 horses, 118 dogs, and 62 bovines were collected and showed 33.8%, 14.4%, and 50.0% of seroprevalence for SFG Rickettsia, respectively. A total of 1,287 ixodid ticks were collected from animals/vegetation and processed in pools for polymerase chain reaction. Among them, 1.7% was positive for Rickettsia genes, and Rickettsia amblyommii, R. rickettsii, and Rickettsia spp. were found. These results confirm the circulation of dengue, different SFG Rickettsia species and the relevance of other etiologies like leptospirosis and human anaplasmosis. Further studies must identify different epidemiological variables to establish proper surveillance and control programs.

Identification of a T-Cell Epitope That Is Globally Conserved among Outer Membrane Proteins (OMPs) OMP7, OMP8, and OMP9 of Anaplasma marginale Strains and with OMP7 from the A. marginale subsp. centrale Vaccine Strain.

Within the protective outer membrane (OM) fraction of Anaplasma marginale, several vaccine candidates have emerged, including a family of OM proteins (OMPs) 7 to 9, which share sequence identity with each other and with the single protein OMP7 in the vaccine strain A. marginale subsp. centrale. A. marginale OMPs 7 to 9 are logical vaccine candidates because they are surface exposed, present in the OM immunogen and protective cross-linked OM proteins, recognized by immune serum IgG2 and T cells in cattle immunized with OM, and recognized by immune serum IgG2 from cattle immunized with the A. centrale vaccine strain. We report the identification of a globally conserved 9-amino-acid T-cell epitope FLLVDDAI/VV shared between A. centrale vaccine strain OMP7 and the related A. marginale OMPs 7 to 9, where position 8 of the peptide can be isoleucine or valine. The epitope is conserved in American A. marginale strains, in the Australia Gypsy Plains strain, and in multiple field isolates from Ghana. This epitope, together with additional T-cell epitopes that are present within these proteins, should be considered for inclusion in a multivalent vaccine for A. marginale that can provide protection against disease caused by globally distributed bacterial strains.

Molecular Evidence of Different Rickettsia Species in Villeta, Colombia.

The aim of this work was to detect and identify Rickettsia species in ticks collected in rural areas of Villeta, Colombia. Tick specimens were collected from domestic animals and walls of houses in five rural villages of Villeta town and from humans in Naranjal village (same town). Moreover, a flea collected from the same area was also processed. DNA was extracted and tested by conventional, semi-nested, and nested PCR reactions targeting rickettsial genes. In the ticks collected from humans from Naranjal village, a nymph of Amblyomma cajennense sensu lato was amplified using primers for ompA and sequenced (100% identity with "Candidatus Rickettsia amblyommii"). Last, three amplicons from the Ctenocephalides felis flea, corresponding to gltA, ompB, and 16S rRNA genes, showed high identity with R. felis (98.5%, 97.3%, and 99.2%, respectively) and "Candidatus Rickettsia asemboensis" (99.7% and 100%, respectively). To our knowledge, these results correspond to the first molecular detection in Colombia of "Candidatus Rickettsia amblyommii" and "Ca. Rickettsia asemboensis" in fleas.

Caso probable de fiebre manchada ( Rickettsia felis) transmitida por pulgas / Probable case of flea-borne spotted fever ( Rickettsia felis )

Rickettsia felis es el agente etiológico de la fiebre manchada transmitida por pulgas, cuyo principal vector y reservorio es Ctenocephalides felis . Típicamente, la enfermedad se presenta como fiebre aguda asociada a cefalea, astenia, exantema máculo-papular generalizado y, en algunos casos, con escara de inoculación. En los últimos años, R. felis ha venido adquiriendo un papel importante en la etiología del síndrome febril agudo, calificándola como una enfermedad emergente y subdiagnosticada. La inmunofluorescencia indirecta es actualmente el método diagnóstico de referencia. Sin embargo, esta técnica presenta limitaciones relacionadas con la reacción cruzada que existe entre las diferentes especies del género Rickettsia . En el presente reporte se describe el caso de un paciente de 16 años con síndrome febril agudo secundario a infección probable por R. felis .

Rickettsia felis is the etiologic agent of flea-borne spotted fever, with Ctenocephalides felis as its main vector and reservoir. Typically, the disease presents as acute fever associated with headache, asthenia, generalized maculo-papular rash, and in some cases, an inoculation eschar. In recent years, R. felis has acquired an important role in the etiology of the acute febrile syndrome; it is indeed an emerging infectious disease, albeit underdiagnosed. Indirect immunofluorescence assay (IFA) is currently the reference diagnostic method. However, this technique has limitations related to the cross reactivity among different species of rickettsiae. Herein, we describe a case of a 16 year-old patient with an acute febrile syndrome secondary to probable infection with R. felis.

[Probable case of flea-borne spotted fever (Rickettsia felis)]. / Caso probable de fiebre manchada (Rickettsia felis) transmitida por pulgas.

Rickettsia felis is the etiologic agent of flea-borne spotted fever, with Ctenocephalides felis as its main vector and reservoir. Typically, the disease presents as acute fever associated with headache, asthenia, generalized maculo-papular rash, and in some cases, an inoculation eschar. In recent years, R. felis has acquired an important role in the etiology of the acute febrile syndrome; it is indeed an emerging infectious disease, albeit underdiagnosed. Indirect immunofluorescence assay (IFA) is currently the reference diagnostic method. However, this technique has limitations related to the cross reactivity among different species of rickettsiae. Herein, we describe a case of a 16 year-old patient with an acute febrile syndrome secondary to probable infection with R. felis.

Factores de riesgo asociados a la miiasis por cochliomyia hominivorax en fincas ganaderas de Puerto Boyacá (Colombia) / Associated risk factors to myiasis by cochliomyia hominivorax on cattle farms in Puerto Boyacá (Colombia)

Se realizó un estudio descriptivo-transversal en el municipio de Puerto Boyacá para identificar los factores de riesgo asociados a la miiasis por Cochliomyia hominivorax en bovinos. En 44 fincas ganaderas seleccionadas en un muestreo por conveniencia, se efectuó una entrevista personal a cada ganadero acerca del uso del suelo, sistema de producción ganadera y productos para el tratamiento de la miiasis traumática, entre el 6 y el 15 de febrero del 2007. El material suministrado para recolección de larvas fue recogido entre la última semana de abril y la primera semana de mayo del 2007. Análisis de frecuencias, medidas de asociación y pruebas no paramétricas fueron utilizados. Se detectaron 49 casos (0,4 por ciento) de miiasis por C. hominivorax en 12.325 bovinos registrados, en 18 (41 por ciento) de 44 fincas ganaderas. La causa de herida más frecuente fue abrasión por alambre de púas en 16 casos (32,7 por ciento). Los lugares de infestación más frecuente fueron el ombligo y el escroto con 9 casos (18,4 por ciento) cada uno. Se encontró asociación entre grupos etarios en bovinos y la presentación de casos por C. hominivorax (P=0,000; α=0,05). Se halló asociación entre el sistema de producción bovina y la presentación de casos por C. hominivorax (P=0,044; α=0,05). Se registró el uso de productos no adecuados en el tratamiento de la miiasis traumática como creolina (31 fincas), gasolina (4 fincas), aceite quemado (2 fincas), Baygon® (1 finca) y Vanodine® (1 finca). Se concluye que las fincas ganaderas seleccionadas compartieron factores de riesgo, según el sistema de producción ganadera. Se requiere intervención para evitar perjuicios en animales y consumidores por la utilización de productos no apropiados.

A Cross-sectional and descriptive study was carried out in countryside of Puerto Boyacá town for identification of Cochliomyia hominivorax myiasis risk factors on cattle. Fourty four cattle farms were selected with a not-random sampling. Personal interviews were carried out to livestock farmers. Land use, livestock production system, and products for treatment of screwworm myiasis were investigated on February 6-15 of 2007. Stuff and instructions were supplied for taking larvae from animal wounds afterwards register survey application. Those materials were collect since last week on April of 2007 until first week on May of 2007. Frequency analysis, cross-tabs measures and non parametric tests were used. 49 screwworm myiasis cases (0.4 percent) out of 12,325 registered cattle were found, in 18 (41 percent) out of 44 selected cattle farms. The main cause of wounds recorded was injury by barbed wire with 16 cases (32.7 percent). Body sites more frequently infested were navel and scrotum with 9 cases (18.4 percent) each one. Association between age group in cattle and screwworm myiasis cases was founded (P=0.000; α=0.05). Association between cattle production system and screwworm myiasis cases was founded (P=0.044; α=0.05). Usual handling of non appropriate products for screwworm myiasis treatment like “creolina” (31 farms), gasoline (4 farms), used motor lubricant oil (2 farms), Baygon® (1 farm) and Vanodine® (1 farm) was registered. It may be concluded that selected cattle farms shared risk factors, depending on cattle production system. It demands epidemiological intervention to avoid damages to animals and consumers for using of inappropriate products for treatment of traumatic myiasis.

Ecología y epidemiología del Gusano Barrenador del Ganado, Cochliomyia hominivorax (Coquerel, 1858) / Ecology and epidemiology of screwworm, Cochliomyia Hominivorax (Coquerel, 1858)

La miasis por cochliomyia hominivorax se caracteriza por áreas manchadas con exudados sanguinolentos alrededor de las heridas de los animales. Sus efectos patológicos van desde la irritación mecánica por la alimentación de las larvas hasta la muerte del hospedero en infestaciones sucesivas. En condiciones naturales, las densidades de las poblaciones de la mosca del Gusano Barrenador del Ganado son bajas. Se distribuyen en relación con los cursos de agua, la proximidad de hospederos potenciales y la densidad de la vegetación. Los climas húmedos y calientes favorecen el incremento de las poblaciones del gusano Barrenador del ganado. Dentro de los animales domésticos, la principal especie afectada es la bovina. Los factores de riesgo en los animales están relacionados, principalmente, con prácticas de manejo. En seres humanos, los niños y los ancianos, en condiciones de abandono y desaseo, son los individuos más vulnerables.Se señalan algunos aspectos técnicos que deben ser analizados en la planeación de estudios ecológicos y epidemiológicos en Colombia...