Juan José Romero-Zúñiga

Novel genotype of Ehrlichia canis detected in samples of human blood bank donors in Costa Rica

This study focuses on the detection and identification of DNA and antibodies to Ehrlichia spp. in samples of blood bank donors in Costa Rica using molecular and serological techniques. Presence of Ehrlichia canis was determined in 10 (3.6%) out of 280 blood samples using polymerase chain reaction (PCR) targeting the ehrlichial dsb conserved gene. Analysis of the ehrlichial trp36 polymorphic gene in these 10 samples revealed substantial polymorphism among the E. canis genotypes, including divergent tandem repeat sequences. Nucleotide sequences of dsb and trp36 amplicons revealed a novel genotype of E. canis in blood bank donors from Costa Rica. Indirect immunofluorescence assay (IFA) detected antibodies in 35 (35%) of 100 serum samples evaluated. Thirty samples showed low endpoint titers (64-256) to E. canis, whereas five sera yielded high endpoint titers (1024-8192); these five samples were also E. canis-PCR positive. These findings represent the first report of the presence of E. canis in humans in Central America.

Molecular Detection and Genotyping of Chlamydia psittaci in Captive Psittacines from Costa Rica.

Oropharyngeal and cloacal swabs from 117 captive psittacine birds presented at veterinary clinics (88) and from shelters/rescue centers of wildlife (29) were collected to determine the prevalence of C. psittaci in captive birds in Costa Rica. Samples were collected during 2009 from a total of 19 different species of parrots, with Ara macao (33), Amazona autumnalis (24), Amazona ochrocephala (21), and Ara ararauna (8) being the most representative species sampled. C. psittaci was detected in four (3.4%) birds using molecular detection (PCR). The positive samples belonged to birds presented at veterinary clinics; three of them were Ara macao and one Amazona ochrocephala. Three birds were adults; all positive birds showed no symptoms of illness and lived in homes with other birds, two in San José and two in Heredia. Sequencing was used to confirm the PCR positive results, showing that two samples of C. psittaci belonged to genotype A, representing the first report of the presence of this genotype in Costa Rica. The detection of this bacterium in captive psittacine birds shows that there is a potential risk for people living or having contact with them and that there is a possibility of infecting other birds.

Detection of Babesia caballi and Theileria equi in Blood from Equines from Four Indigenous Communities in Costa Rica

A cross-sectional study was carried out in four indigenous communities of Costa Rica to detect presence and prevalence of Babesia caballi and Theileria equi and to investigate factors associated with presence of these hemoparasites. General condition of horses (n = 285) was evaluated, and hematocrits and hemoglobin were determined from blood samples of 130 horses, which were also analyzed using blood smears, nested polymerase chain reaction (PCR), and immunosorbent assay (c-ELISA). The general condition of the horses (n = 285) in terms of their body and coat was between regular and poor, and hematocrit and hemoglobin average values were low (19% and 10.65 g/dL, resp.). Erythrocyte inclusions were observed in 32 (24.6%) of the samples. Twenty-six samples (20.0%) gave positive results for B. caballi and 60 (46.2%) for T. equi; 10 horses (7.7%) showed mixed infection, when analyzed by PCR. Using c-ELISA, it was found that 90 (69.2%) horses had antibodies against B. caballi and 115 (88.5%) against T. equi, while 81 (62.3%) showed mixed reactions. There were no factors associated with the presence of B. caballi and T. equi. These results contrast with results previously obtained in equines in the Central Valley of Costa Rica.

Serology, molecular detection and risk factors of Ehrlichia canis infection in dogs in Costa Rica.

A cross-sectional study combining different serological and molecular techniques for the detection of Ehrlichia species in dogs and their ticks was carried out with data from all regions of Costa Rica. A seroprevalence of 32.1% (131/408), and infection with E. canis of 3.2% (13/407) was found, whereas 6.9% (9/130) of ticks attached to the dogs were PCR positive to E. canis. Higher prevalences were found outside the Greater Metropolitan Area (GMA). Risk factors associated with E. canis seropositivity were age, between 2 and 7 years (RR: 1.6, 95% CI: 1.2-2.2) and 8-15 years (RR: 1.8, 95% CI: 1.2-3.0), number of dogs/total of households [Dogs per Household Ratio (DHR) ≥3.1 (RR: 2.0; 95% CI: 1.4-3.0)], number of dogs infested with at least one tick/total of dogs sampled [Tick Infestation Prevalence (TIP)≥31% (RR: 2.1; 95% CI:1.3-3.3)] and living outside the GMA (RR: 1.7; 95% CI: 1.2-2.4) and being a mixed-breed dog (RR: 1.5; 95% CI: 1.1-2.1). Risk factors for E. canis PCR positive dogs were a depressive attitude (OR: 11.2; 95% CI: 1.1-115.9), fever (OR:4.8; 95% CI:1.2-19.3), DHR≥3.1 (OR: 5.7; 95% CI:1.7-19.2)], number of ticks/total of dogs sampled [Tick Distribution Ratio (TDR) ≥2.1 (OR: 6.5; 95% CI: 1.3-31.8)], and TIP≥40% (OR: 5.7; 95% CI: 1.7-19.2). This paper describes E. canis seroprevalence, PCR prevalence and tick analysis in dogs from Costa Rica, with associated clinical signs and owner perceptions. In summary, most of the E. canis infections in dogs in our country seemed to pass unnoticed by owners. Since most of the seropositive dogs (97.7%, 131/134) were negative for E. canis DNA in their blood, it is important to determine in future studies if these dogs recovered from the E. canis infection without any medication, or are persistently infected, and will develop chronic disease.

Molecular Detection of Plasmodium malariae/Plasmodium brasilianum in Non-Human Primates in Captivity in Costa Rica.

One hundred and fifty-two blood samples of non-human primates of thirteen rescue centers in Costa Rica were analyzed to determine the presence of species of Plasmodium using thick blood smears, semi-nested multiplex polymerase chain reaction (SnM-PCR) for species differentiation, cloning and sequencing for confirmation. Using thick blood smears, two samples were determined to contain the Plasmodium malariae parasite, with SnM-PCR, a total of five (3.3%) samples were positive to P. malariae, cloning and sequencing confirmed both smear samples as P. malariae. One sample amplified a larger and conserved region of 18S rDNA for the genus Plasmodium and sequencing confirmed the results obtained microscopically and through SnM-PCR tests. Sequencing and construction of a phylogenetic tree of this sample revealed that the P. malariae/P. brasilianum parasite (GenBank KU999995) found in a howler monkey (Alouatta palliata) is identical to that recently reported in humans in Costa Rica. The SnM-PCR detected P. malariae/P. brasilianum parasite in different non-human primate species in captivity and in various regions of the southern Atlantic and Pacific coast of Costa Rica. The similarity of the sequences of parasites found in humans and a monkey suggests that monkeys may be acting as reservoirs of P.malariae/P. brasilianum, for which reason it is important, to include them in control and eradication programs.

Variations in the Temperature-Humidity Index and Dorsal Fat Thickness during the Last Trimester of Gestation and Early Postpartum Period Affect Fertility of Bos indicus Cows in the Tropics

In order to measure the influence of the temperature-humidity index (THI) and the variation of fat thickness on reproductive performance, ninety-two Bos indicus cows kept under grazing conditions were used in two farms in Veracruz (Mexico) and Puntarenas (Costa Rica). THI was calculated with the average environmental temperature and relative humidity. Measurements of fat thickness (FAT) were taken two weeks apart from the last trimester of gestation to approximately 80 days postpartum (dpp). Natural breeding was used in both farms. Time to conception was calculated based on the interval from days at risk to conception (DRC), which had to be at least 28 dpp. THI was between 65.4 ± 2.9 and 73.2 ± 1.5 in Veracruz and 75.4 ± 0.26 and 76.5 ± 0.55 in Puntarenas. Variations in THI were observed in Puntarenas whereas in Veracruz THI variations were more prominent. In Veracruz, loss of fat during the last trimester of gestation was on average 8.5%, whereas in the postpartum period it was 18.4% (P = 0.042). In Puntarenas, the variation in the last trimester of gestation was on average 18.7% and in the postpartum period was 10.5% (P = 0.012). The relative change in FAT in Veracruz was 36.7%, and in Puntarenas it was 29.3%. Overall, 60% of the cows became pregnant. FAT decreased the interval of DRC (R2=0.06; P=0.033) with a high relationship (R2=0.76; P< 0.0001) between THI and time to conception, in both farms. In conclusion, THI levels influence the reproductive performance in early postpartum period affecting DRC.

Understanding Ehrlichia canis Infections in Dogs of Costa Rica: Hematological Findings and Indicative Clinical Signs

Background: A cross-sectional study combining different serological and molecular techniques for the detection of Ehrlichia canis in dogs was carried out to determine hemopathological findings and suggestive clinical signs associated with acute, subclinical and chronic infections in the dog population of Costa Rica. Objectives: The present study describes and analyzes, in a more representative sampling frame, the clinical and hematological presentation of E. canis infection in dogs of Costa Rica in all its clinical stages. Methods: A descriptive analysis of the clinical signs was performed from a 441-dog sample. Serological and molecular techniques for the detection of Ehrlichia canis in dogs were applied. One and two-way ANOVA were carried out to determine the effect of the infection status on the hematological parameters. Results: A total of 0.7% (3/407) dogs were found with acute (seronegative but PCR positive), 29.7% (121/407) with subclinical (seropositive and PCR negative), and 2.5% (10/407) with chronic (seropositive and PCR positive) E. canis infections. Significant hemopathological findings were determined in dogs with acute (thrombocytosis), subclinical and chronic (anemia, thrombocytopenia, leukopenia) E. canis infections. Conclusions: Future studies must determine if dogs with subclinical E. canis infections eliminated the agent without any medication, or if they continue to be persistently infected, and will develop the chronic disease at some point in their lives.

EFECTOS DE LA ENDOGAMIA SOBRE PARÁMETROS REPRODUCTIVOS EN VACAS HOLSTEIN Y JERSEY DE COSTA RICA

Resumen es: El objetivo de este trabajo fue analizar el efecto de los niveles de consanguinidad (F) en vacas Holstein y Jersey nacidas entre enero de 1995 y dicie...

Effects of inbreeding on reproductive parameters of Costa Rican Holstein and Jersey cows.

Resumen es: El objetivo de este trabajo fue analizar el efecto de los niveles de consanguinidad (F) en vacas Holstein y Jersey nacidas entre enero de 1995 y dicie...