José I. González-Rojas

Serologic evidence of West Nile virus infection in horses, Coahuila State, Mexico.

Serum samples were obtained from 24 horses in the State of Coahuila, Mexico, in December 2002. Antibodies to West Nile virus were detected by epitope-blocking enzyme-linked immunosorbent assay and confirmed by plaque reduction neutralization test in 15 (62.5%) horses. We report the first West Nile virus activity in northern Mexico.

West Nile Virus Isolation in Human and Mosquitoes, Mexico

West Nile virus has been isolated for the first time in Mexico, from a sick person and from mosquitoes (Culex quinquefasciatus). Partial sequencing and analysis of the 2 isolates indicate that they are genetically similar to other recent isolates from northern Mexico and the western United States.

Serologic evidence of west nile virus infection in birds, Tamaulipas State, México

Following the introduction of West Nile virus (WNV) into North America in 1999, surveillance for WNV in migratory and resident birds was established in Tamaulipas State, northern México in December 2001. Overall, 796 birds representing 70 species and 10 orders were captured and assayed for antibodies to WNV. Nine birds had flavivirus-specific antibodies by epitope-blocking enzyme-linked immunosorbent assay; four were confirmed to have antibody to WNV by plaque reduction neutralization test. The WNV-infected birds were a house wren, mourning dove, verdin and Bewicks wren. The house wren is a migratory species; the other WNV-infected birds are presumably residents. The WNV-infected birds were all captured in March 2003. These data provide the first indirect evidence of WNV transmission among birds in northern México.

Phylogenetic Analysis of West Nile Virus, Nuevo Leon State, Mexico

West Nile virus RNA was detected in brain tissue from a horse that died in June 2003 in Nuevo Leon State, Mexico. Nucleotide sequencing and phylogenetic analysis of the premembrane and envelope genes showed that the virus was most closely related to West Nile virus isolates collected in Texas in 2002.

GONOTROPHIC CYCLE AND SURVIVORSHIP OF CULEX QUINQUEFASCIATUS (DIPTERA: CULICIDAE) USING STICKY OVITRAPS IN MONTERREY, NORTHEASTERN MEXICO

ABSTRACT Mark–release–recapture experiments were conducted to determine the length of the gonotrophic cycle and rate of survivorship of Culex quinquefasciatus Say in Monterrey, northeastern Mexico. A total of 2,352 field-caught Cx. quinquefasciatus females were marked and released at 8–12 h postemergence in 2 field trials. Sticky ovitraps were used to recapture marked gravid females. One hundred and ten (4.6%) marked females were recaptured during a 12-day sampling period. Recapture rates for the 2 individual trials were 6.4% and 3.5%. The length of the gonotrophic cycle, calculated as the average time between the initial blood meal and the time of recapture of gravid females, was 2–3 days. The first blood-fed mosquitoes were recaptured on the 2nd day postrelease. Gravid egg-laying females were most commonly recaptured at 2–3 days postfeeding. Daily survival estimates for the 2 release dates were of 0.871 and 0.883, respectively.

Host-feeding preference of Culex quinquefasciatus in Monterrey, northeastern Mexico.

ABSTRACT Studies were conducted to determine the host selection patterns of Culex quinquefasciatus in the municipalities of Guadalupe and Escobedo near Monterrey, northeastern Mexico. Mosquitoes were captured inside and outside houses. Chickens and humans were the most common blood sources for all Cx. quinquefasciatus females, accounting for nearby 70% of blood meals. Human blood was detected by enzyme-linked immunosorbent assay in 36.4% and 28.4% of engorged females resting inside houses in Guadalupe and Escobedo, respectively. The proportions of indoor resting females fed on chicken blood were 38.7% and 56.7%, respectively. The weighted and unweighted human blood index (HBI) values were calculated, by using indoor and outdoor data, from the proportions of humanfed mosquitoes. Weighted means (HBI) estimates for Guadalupe and Escobedo were 23.0% and 15.4%, respectively. The forage ratios (FRs) for humans were <1.0 (with or without chicken populations); consequently, it seems that these mosquitoes feed on humans with less frequency in comparison with chickens, horses, and pigs. The FRs for chickens were the highest of all available hosts (1.7 and 3.2), and they were the most abundant hosts in Escobedo, and the second most abundant in Guadalupe, indicating a selective bias of Cx. quinquefasciatus for chickens (i.e. ornithophagic).

High fidelity to wintering, stop-over and breeding sites shown by a Long-billed Curlew Numenius americanus tracked with satellite telemetry on migratory flights across North America

Capsule We studied the migratory movements and site fidelity of a male Long-billed Curlew using satellite telemetry in North America; the bird completed three migratory cycles and showed strong fidelity to stop-over, breeding, and wintering sites, not only on a geographical scale but also on a local scale across the years.

Molecular phylogenetic analysis of an endangered Mexican sparrow: Spizella wortheni

The Worthens Sparrow (Spizella wortheni) is an endemic bird species of the Mexican Plateau that is protected by Mexican law. Considering its limited range (25 km(2)), small population size (100-120 individuals), and declining population, it is one of the most endangered avian species in North America. Although it has been assumed to be the sister taxon of the Field Sparrow (Spizella pusilla), the systematic and evolutionary relationships of Worthens Sparrow have never been tested using modern molecular phylogenetic methods. We addressed the molecular phylogeny of S. wortheni analyzing six mitochondrial genes (3571 bp) from all of the natural members of the genus Spizella. Our maximum likelihood and Bayeasian analysis indicate that despite the superficial similarity, S. wortheni is not the sister taxon of S. pusilla, but is instead most closely related to the Brewers Sparrow (Spizella breweri). Also new insights about the phylogenetics relationships of the Spizella genera are presented.

Molecular Cloning and Characterization of the Circadian Clock Timeless Gene in Culex quinquefasciatus Say (Diptera: Culicidae)

Abstract. In eukaryotes, the timeless (TIM) gene plays a fundamental role in the control of the circadian clock by regulating several biochemical, physiological, and behavioral processes. RT-PCR was used to amplify TIM mRNA from larval southern house mosquito, Culex quinquefasciatus Say, from three locations in the State of Nuevo Leon in northeastern Mexico. The 3062 bp TIM cDNA was assembled from three overlapping PCRs that were cloned and sequenced. DNA sequence analysis used amplified cDNA fragments to complete coding the DNA sequence (2991 bp). Tim ORF consisting of 996 codons was shorter than the orthologous genes from other mosquito species. A series of deletions in the core sequence of TIM were detected. No other amplification products were visualized, and thus, the possibility of alternative spliced mRNA species was discarded. Because TIM is a widely conserved gene in eukaryotes, and maintaining colonies of Cx. quinquefasciatus is easy, determining the sequence of the TIM gene in the mosquito provides the possibility of its use as a model for circadian clock experimentation.

First nesting record of the long-eared owl (Asio otus) for Chihuahua, Mexico

Abstract We found two nests of the long-eared owl (Asio otus) in Reserva Ecológica el Uno, located in Janos municipality, Chihuahua, Mexico. Contents of nests were recorded, photographed, and monitored between 28 March and 10 June 2007. Nests were constructed on honey mesquites (Prosopis glandulosa) and contained three eggs and three nestlings, respectively. These nests represent the first confirmed breeding record for the state of Chihuahua and the second for Mexico (outside Baja California).