Eimeria atricillae n. sp. (Apicomplexa: Eimeriidae) from the laughing gull Leucophaeus atricilla (Linnaeus) (Aves: Charadriiformes: Laridae) in Port Isabel, Texas

A new coccidian species, Eimeria atricillae n. sp. (Apicomplexa: Eimeriidae) collected from the laughing gull Leucophaeus atricilla, is reported from Port Isabel, Texas, USA. Sporulated oöcysts of the new species are spherical to subspherical, 16.0-18.1 × 14.4-16.6 (17.1 × 15.4) μm, with a length/width (L/W) ratio of 1.0-1.1; polar granules are present, but micropyle and oöcyst residuum are absent. Sporocysts are ovoid, 9.1-9.7 × 6.1-7.1 (9.4 × 6.6) μm, with a L/W ratio of 1.3-1.5; Stieda body present, but sub-Stieda and para-Stieda bodies are absent; sporocyst residuum diffuse.

First Report of Intestinal Cestode Infection in a Berylline Hummingbird (Saucerottia beryllina) in Mexico

BACKGROUND

Up to now, five cestode species have been reported infecting five hummingbird species. To date, there have been no reports of cestode infections in hummingbirds in Mexico.

METHODS

A Berylline hummingbird (Saucerottia beryllina) was found dead in a backyard at Toluca City, Mexico, and a window collision was assumed as the cause of death. The bird was preserved in 10% neutral buffered formalin for routine histological examination.

RESULTS

At the histological study, liver parenchymal disruption was observed. This lesion could be the result of the assume collision. No lesions were observed in other tissues examined. Conspicuous cestode structures were observed in the lumen of the small intestine. Structure of cestodes, as revealed from histological sections, suggests their position in the genus Anonchotaenia Cohn, 1900 (family Paruterinidae).

CONCLUSION

This is the first report of intestinal cestodosis in a Berylline hummingbird (S. beryllina) in Mexico.

Eimeria erythrorhynchosi n. sp. (Apicomplexa: Eimeriidae) from the American white pelican Pelecanus erythrorhynchos Gmelin, 1789 (Pelecaniformes: Pelecanidae) in Toluca, Mexico

A new coccidian species, Eimeria erythrorhynchosi n. sp. (Apicomplexa: Eimeriidae) collected from the American white pelican Pelecanus erythrorhynchos Gmelin 1789, is reported from Toluca city, Mexico. Sporulated oocysts of the new species are ovoidal, 17.5-19.6 × 14.1-14.8 (18.5 × 14.5) μm, with a length/width (L/W) ratio of 1.0-1.5 (1.25); micropyle present, robust and protruding, W: 4.5-5.5, and polar body (1 or 2), L × W: 2.5 (2-3), associated with the micropyle; oocyst residuum absent. Sporocysts are ovoidal, 10.1-11.2 × 6.4-7.1 (10.7 × 6.8) μm, with a length/width (L/W) ratio of 1.0-1.6 (1.3); Stieda and sub-Stieda bodies are both present, but para-Stieda body is absent; sporocyst residuum of diffuse granules. Sporozoites are vermiform, 9.6 × 2.4 μm. The new species is the seventh species of Eimeria recorded in Pelecaniformes and the third in Pelecanidae.

Isospora speciosae n. sp. (Apicomplexa: Eimeriidae) from the black-polled yellowthroat Geothlypis speciosa Sclater, 1859 (Passeriformes: Parulidae) in Ciénegas del Lerma, Mexico

A new coccidian species, Isospora speciosae n. sp. (Apicomplexa: Eimeriidae) collected from the black-polled yellowthroat Geothlypis speciosa Sclater, is reported from the marsh Ciénegas del Lerma Natural Protected Area, Mexico. Sporulated oöcysts of the new species are subespherical to ovoidal, 24-26 × 21-23 (25.7 × 22.2) μm, with a length/width (L/W) ratio of 1.1; one or two polar granules are present, but micropyle and oöcyst residuum are absent. Sporocyts are ovoidal, 17-19 × 9-11 (18.7 × 10.2) μm, with a L/W ratio of 1.8; Stieda and sub-Stieda bodies are both present, but para-Stieda body is absent; sporocyst residuum compact. The new species is the sixth species of Isospora recorded in a bird of the family Parulidae in the New World.

Enteroparasites from the American White Pelican (Pelecanus erythrorhynchos) in Toluca Valley, Mexico

We examined 82 fresh fecal samples from American White Pelican (Pelecanus erythrorhynchos) at San Pablo Autopan, Toluca Valley, central Mexico, December 2021 to April 2022. Eggs of Contracaecum spp. were observed in 100%, Capillaria spp. in two (2.5%), Strongyloides spp. in eight (9.7%), and coccidial oocysts in 12 (15%).

Prevalencia de genes qnrB, qnrA y blaTEM en bacteriófagos atemperados de Escherichia coli aislados en agua residual y alcantarillas de rastros del Estado de Méxicoesidual y alcantarillas de rastros de la zona norte del Estado de México

Los genes de resistencia a los antibióticos (ARG) han sido descritos principalmente en bacterias; sin embargo, en fagos atemperados los estudios han sido escasos. En este estudio se determinó la prevalencia de los genes qnrB, qnrA y blaTEM en cepas de Escherichia coli y en fagos atemperados obtenidos por inducción del ciclo lítico en dichos aislamientos. Se recolectaron 48 muestras de agua potable, agua residual y alcantarillado en rastros del Estado de México obteniendo 37 aislamientos de E. coli. La mayor resistencia fue para tetraciclina 32/37 (86.4 %), seguido de trimetoprim-sulfametoxasol 19/37 (51.3 %) y por último ampicilina y ácido nalidíxico con el mismo número de aislamientos 18/37 (48.6 %). La prevalencia del gen blaTEM en aislamientos bacterianos fue 37.8 %, mientras que en los aislamientos fágicos fue 3.5 %.  Los genes qnrA  y  qnrB  fueron encontrado s en 8.1 % y 29.7 % respectivamente en aislamientos bacterianos, mientras que en los aislamientos fágicos fueron obtenidos 2.7 y 24.3 % respectivamente. Los resultados muestran que los ARG presentes en aislamientos bacterianos se relacionan en el ADN fágico, lo que indica el papel significativo en la propagación de ARG en los rastros estudiados. Comprender los mecanismos de resistencia a antimicrobianos, permitirá establecer medidas efectivas para disminuir este fenómeno.

Identification, HPG2 Sequence Analysis, and Antimicrobial Susceptibility of Avibacterium paragallinarum Isolates Obtained from Outbreaks of Infectious Coryza in Commercial Layers in Sonora State, Mexico

This is the first extensive report on the identification and characterization of Avibacterium paragallinarum (AVP) isolates obtained from outbreaks of infectious coryza (IC) in IC-vaccinated layer flocks from Sonora State in Mexico. Isolates obtained from IC outbreaks during the years 2007, 2014, 2015, 2017, and 2019 were identified by conventional PCR test and 16S rRNA gene analysis, serotyped by Page serotyping and genotyped by the recently described partial sequence analysis of the HPG2 region. Furthermore, antimicrobial susceptibility profiles were determined by a recently improved minimal inhibitory concentration (MIC) test. The conventional PCR test and the 16S rRNA analyses confirmed the isolates as AVP. Serotyping results showed the involvement of isolates belonging to serotypes A, B, and C in the IC outbreaks. Genotyping of the HPG2 region revealed the presence of sequence type (ST)1, ST4, and ST11, of which the latter has also been identified in Europe. The MIC susceptibility test showed that all tested isolates were susceptible for the majority of tested antimicrobials, including erythromycin and tetracycline, which are important antibiotics for the treatment of IC. The IC situation in Sonora State, Mexico, is complex because of the presence of serotypes A, B, and C. This finding emphasizes the importance of biosecurity in combination with the application of the most optimal vaccination programs in the control of IC in Sonora State, Mexico.

In vitro transduction of antimicrobial resistance genes into Escherichia coli isolates from backyard poultry in Mexico

The transmission of multidrug-resistant pathogens and antimicrobial resistance genes is an emerging problem involving multiple factors (humans, domestic animals, wildlife). The aim of this study was to investigate the presence of Escherichia coli isolates with different antimicrobial resistance genes from backyard poultry and to demonstrate the in vitro transduction phenomenon of these genes between phages from migratory wild birds and poultry E. coli isolates. We collected 197 E. coli isolates from chickens, turkeys, and ducks in backyard production units (northern region of the State of Mexico). Isolates were resistant to ampicillin (80.7%), tetracycline (64.4%), carbenicillin (56.3%), and nalidixic acid and trimethoprim-sulfamethoxazole (both, 26.9%). Moreover, the genes bla_TEM (56.3%), tetB (20.8%), tetA (19.2%), sulI (7.6%), sulII (10.1%), qnrA (9.6%), and qnrB (5.5%) were found. In vitro transduction using phages from migratory wild birds sampled in the wetland Chimaliapan (State of Mexico) was successfully achieved. It was possible to transduce qnrA, tetB, bla_TEM, and sulII genes to E. coli isolates from poultry. This is the first report that describes the transduction of antimicrobial resistance genes from phages of migratory wild birds to poultry and suggests the possible transmission in backyard production units.

Uso de una PCR anidada para el diagnóstico del virus de la necrosis pancreática infecciosa (VNPI) en truchas de campo

El aislamiento en cultivo celular es el método principal para el diagnóstico del virus de la necrosis pancreática infecciosa (VNPI). Aunque es un método confiable, resulta costoso y conlleva tres semanas en proporcionar un resultado. Para disminuir el tiempo en el diagnóstico y aumentar la sensibilidad para la detección del VNPI, el objetivo del presente estudio fue establecer y evaluar el uso de una PCR anidada (PCRa) para un diagnóstico rápido del VNPI. Para ello, se diseñaron dos pares de iniciadores basados en secuencias mexicanas. El primer par (RT-PCR) amplificó un producto de 682 pb y el segundo par (PCRa) 229 pb del gen VP2. Posteriormente, se infectaron 70 crías de truchas arcoíris (Oncorhynchus mykiss) con la cepa virulenta MEX3-CSM-05 a una dosis de 1X105.8 DICC50%/0.02 ml. De cada organismo se colectó el riñón, el bazo, los sacos pilóricos, el hígado, el intestino y las branquias. Para evaluar las pruebas, se utilizaron 26 truchas adultas clínicamente sanas de granjas comerciales del Estado de México. La frecuencia de detección del VNPI mediante RT-PCR en las branquias fue de 87.1 %, en el hígado 61.4 %, en los sacos pilóricos 61.4 %, en el riñón 58.6%, en el intestino 35.7 % y en el bazo 32.9 % (P<0.05). Las muestras negativas a la RT-PCR resultaron positivas en la PCRa. Asimismo, se mostraron positivas las muestras de los órganos de las truchas de campo. En conclusión, la RT-PCR tuvo menor sensibilidad que la PCRa, la cual mostró una sensibilidad del 100%. Por lo tanto, la PCRa es mejor para un diagnóstico confiable del VNPI en peces infectados y enfermos.

Isospora dipperia n. sp. (Apicomplexa: Eimeriidae) from the American dipper Cinclus mexicanus Swainson (Passeriformes: Cinclidae) in Yosemite National Park, USA

Isospora dipperia n. sp. is described from the feces of the American dipper Cinclus mexicanus Swainson collected in Yosemite National Park, California, USA. Sporulated oöcysts of the new species are subespherical, 20-24 × 17-21 (20.9 × 18.7) μm, with a length/width (L/W) ratio of 1.0-1.1 (1.1); one polar granule is present, but micropyle is absent. Sporocyts are lemon-shaped, 14-16 × 8-11 (15.5 × 9.8) μm, with a L/W ratio of 1.6; prominent Stieda and sub-Stieda bodies are both present, but para-Stieda body is absent. Sporocyst residuum of many scattered granules is present and the sporozoites have prominent anterior and posterior refractile bodies. The mean dimensions (15.9 × 13.8 µm) of unsporulated oöcysts of I. cincli Gottschalk, 1972 from the white-throated dipper C. cinclus (L.) in Europe, appear to be considerably smaller than those in I. dipperia n. sp. Comparisons of Isospora dipperia n. sp. with two species of Isospora Schneider, 1881 described in the Americas from birds of the family Sturnidae, related to Cinclidae, revealed that the mean dimensions of the sporulated oöcysts in the new species are considerably smaller than those in I. graculai Bhatia, Chauhan, Arora & Agrawal, 1973 from Gracula religiosa (24.6 × 22.4 µm) and I. rothschildi Upton, Wilson, Norton & Greiner, 2001 from Leucopsar rothschildi (22.3 × 21.6 µm). The new species is the first species of Isospora recorded in a bird of the family Cinclidae in the New World.

The common gallinule, Gallinula galeata (Aves: Gruiformes: Rallidae), as a new host for Eimeria paludosa (Apicomplexa: Eimeriidae) in Mexico

Up to now, four coccidian species have been identified in Rallidae (Aves: Gruiformes): Eimeria mongolica, E. alakuli, E. paludosa and E. porphyrulae. Here, we described an Eimeria species, E. paludosa, from a common gallinule (Gallinula galeata) in Mexico. Oocysts were ovoid and wall pitted single-layered. A prominent micropyle was present, the oocyst residuum absent and the polar granule was present. On histological examination of tissues, endogenous stages (meronts, microgametocytes and macrogametocytes) were seen in the epithelial cells of the small intestine (upper and lower intestine). In addition to a new locality, this is the first description of E. paludosa from G. galeata and is the third description of a coccidian infecting Rallidae in the Americas.

Virulence of infectious pancreatic necrosis virus (IPNV) isolates from Mexico

Infectious pancreatic necrosis virus (IPNV) causes economic losses in Mexican rainbow trout industry. In this study, virulence and genetic fingerprints of Mexican IPNV isolates was investigated for the first time. Two Mexican IPNV isolates were analyzed in rainbow trout fry and the Sp strain was included as high virulence. One of the Mexican IPNV isolate was obtained from diseased fish and the other from fish without clinical signs. The infection was performed using a standardized immersion. Clinical signs were observed at 4 days post infection in fry group infected with strain Sp, two days earlier than in trout infected with IPNV isolates Mexican. Severe lesions were found in 100% of the individuals of Sp group, but only in 25% of each isolated Mexican group. Results suggest that Mexican IPNV isolates are pathogenic, but less virulent than strain Sp. The amino acid motif residues of both Mexican isolates, corresponded to a subclinical disease. Nevertheless, the accumulated motility observed in the field, suggest that other factors play a role in the virulence of the disease.

Isospora toxostomai n. sp. (Apicomplexa: Eimeriidae) from the curved-billed thrasher Toxostoma curvirostre (Swainson) (Passeriformes: Mimidae) at the Central highlands of Mexico

Isospora toxostomai n. sp. (Apicomplexa: Eimeriidae) is described based on material from the curved-billed thrasher Toxostoma curvirostre (Swainson) in the Central Highlands of Mexico. The new species possesses subspherical oöcysts, with a smooth, bi-layered wall. Sporulated oöcysts measure 22-25 × 21-24 (23.4 × 22.3) µm; length/width (L/W) ratio of 1.0-1.1 (1.1). Sporocysts are ellipsoidal, 15-17 × 10-11 (15.8 × 10.5); L/W ratio of 1.3-1.6 (1.5). Micropyle and oöcyst residuum are both absent, and a polar granule present (many fibrils). Mean dimensions of both sporulated oöcysts and sporocysts of I. toxostomai n. sp. appear to be considerably larger than those of Isospora mimusi Coelho, Berto, Neves, Oliveira Flausino & Lopes, 2011 from the tropical mockingbird Mimus gilvus (Vieilot) in Brazil. This is the second species of Isospora Schneider, 1881 infecting a host of the Mimidae in the Americas.

Molecular Identification and Virulence Potential of the Genus Aeromonas Isolated from Wild Rainbow Trout (Oncorhynchus mykiss) in Mexico

The members of the Aeromonas genus are important foodborne pathogens, with a worldwide distribution. Wild rainbow trout, from the national protected area Santuario del Agua State Park, Corral de Piedra, were analyzed. Species of Aeromonas were isolated from the trout, and their pathogenic potential was analyzed based on different pathogenicity and virulence factors. The isolates were identified as A. allosaccharophila (n = 15), A. sobria (n = 8), A. veronii (n = 3), A. rivipollensis (n = 2), A. piscicola (n = 2), and A. popoffii (n = 1), by RNA polymerase sigma factor (rpoD) gene sequencing. Sequence similarity with the type strain was 92.2 to 99.6% for A. sobria isolates, 97.8 to 98.0% for A. allosaccharophila isolates, 99.2% for the A. popoffii isolate, 99.2 to 100% for A. piscicola isolates, and 98.2 to 99.2% for A. veronii isolates. Notably, isolates A30T2-gills and A30T2-spleen showed sequence similarity of 98.0% with strain A. media CECT 4232T and 99.0% with strain A. rivipollensis P2G1T. Virulence genes were detected by PCR at the following frequencies: fla and serine protease, 96.77%; aerA, 93.54%; aexT, 87.09%; lipases, 74.19%; ascV and ahyB, 67.74%; exu, 61.29%; act, 41.93%; ascF-G, 38.70%; lafA, 32.26%; alt, 6.46%; aopP, 9.67%; and ast, 3.23%. These results indicate that several Aeromonas species had the potential pathogenicity to infect wild rainbow trout in the waterway created by the Corral de Piedra dam, suggesting they could be an emerging zoonotic pathogen.

Eimeria aegoliusia n. sp. (Sporozoa: Eimeriidae) from the northern saw-whet owl Aegolius acadicus (Gmelin) (Strigiformes: Strigidae) in Mexico

A new coccidian species (Chromista: Sporozoa: Eimeriidae) collected from the northern saw-whet owl Aegolius acadicus (Gmelin) is reported from Mexico. Eimeria aegoliusia n. sp. has subspherical oöcysts, with smooth, bi-layered wall. Micropyle and oöcyst residuum are both absent and a polar granule is present. To date, eight species of Eimeria Schneider, 1875 have been described from strigiform birds. Mean dimensions of sporulated oöcysts (23.7 × 22.4 µm) and sporocysts (12.8 × 8.3 µm) appear to be considerably smaller than those from other Eimeria spp. with owl definitive hosts: E. atheni Chauhan & Jain, 1979; E. megabubonis Upton, Campbell, Weigel & McKown, 1990; E. spenotytoi Carini, 1939; E. strigis Kutzer, 1963; and E. varia Upton, Campbell, Weigel & McKown. Dimensions of these sporulated oöcysts appear to be larger than those in E. bemricki Averbeck, Cooney, Guarnera, Redig & Stromberg, 1998. The presence of polar granules and their number allowed differentiation from E. bubonis Cawthorn & Stockdale, 1981 and E. nycteae Volf, Koudela & Modry, 1999. This is the first description of an eimeriid coccidian infecting A. acadicus.

Phenotypic and genotypic profile of clinical and animal multidrug-resistant Salmonella enterica isolates from Mexico

AIMS

The objective of this study was to obtain a phenotypic and genotypic profile of Salmonella enterica including multidrug-resistant (MDR) isolates from food-producing animals and clinical isolates, as well as their genetic relatedness in two different States of Mexico (Jalisco and State of Mexico).

METHODS AND RESULTS

A total of 243 isolates were evaluated in terms of antimicrobial resistance (AMR) and related genes through a disk diffusion method and PCR respectively; we found 16 MDR isolates, all of them harbouring the bla_CMY gene but not qnr genes, these isolates represent less than 10% of the collection. The pulsed-field gel electrophoresis revealed a higher genotypic similitude within isolates of State of Mexico than Jalisco.

CONCLUSIONS

A low percentage of Salmonella isolates were resistant to relevant antibiotics in human health, nevertheless, the AMR and involved genes were similar despite the different serovars and origin of the isolates.

SIGNIFICANCE AND IMPACT OF THE STUDY

This investigation provided an insight of the current status of AMR of Salmonella isolates in two States of Mexico and pinpoint the genes involved in AMR and their epidemiological relationship, the information could help to determine an adequate therapy in human and veterinary medicine.

Virulence of Serovar C-1 Strains of Avibacterium paragallinarum

The bacterium Avibacterium paragallinarum is the etiologic agent of infectious coryza of chickens. There are nine serovars of A. paragallinarum , and serovar C-1 has emerged in outbreaks of infectious coryza in layer hens in the Americas, with all isolates having been obtained from infectious coryza-vaccinated chickens. In the current study, the clinical and histopathologic outcomes of experimental infections in chickens with A. paragallinarum of serovar C-1 were investigated. The Japanese serovar reference strain, H-18, and a Mexican isolate, ESV-135, were included in the study. No differences in clinical sign scores or morbidity were observed between the two strains. The two bacterial strains caused microscopic lesions of lymphoplasmacytic inflammation in the mucosa of the nasal cavity, infraorbital sinus, and trachea. Similar severe lesions were observed in birds inoculated with both H-18 and ESV-135 strains. The lesions were present 48 hr after inoculation and persisted until day 10 after inoculation. Slight to severe, extensive hemorrhages were observed in the lumen, mucous membranes, and lamina propria of the nasal cavity and infraorbital sinus in most of the chickens inoculated with either the reference strain H-18 or the ESV-135 isolate. Hemorrhages in the upper respiratory tract of chickens experimentally infected with A. paragallinarum are reported here for the first time. The results have confirmed the high virulence of the reference strain H-18 as previously reported and have shown that the Mexican isolate was as virulent as the reference strain. The virulence of A. paragallinarum isolates may play a role in explaining why severe infectious coryza outbreaks are being seen in both vaccinated and nonvaccinated chicken flocks.

<i>Eimeria</i> <i>atlapetesi</i> nom. nov., a replacement name for <i>Eimeria</i> <i>pileata</i> Soriano-Vargas et al., 2015 (Apicomplexa: Eimeriidae), preoccupied by <i>Eimeria</i> <i>pileata</i> Straneva and Kelley, 1979 (Apicomplexa: Eimeriidae), with observations on histopathology and phylogenetic analysis

Eimeria pileata Soriano-Vargas, Medina, Salgado-Miranda, García-Conejo, Galindo-Sánchez, Janczur, Berto and Lopes, 2015 is a junior homonym of Eimeria pileata Straneva and Kelley, 1979 and needs to be replaced. This coccidium was described from a rufous-capped brush finch Atlapetes pileatus Wagler in the Nevado de Toluca Natural Protected Area, Mexico. Thus, to maintain the original intent of the specific epithet derived from the scientific name of the type-host, the name Eimeria atlapetesi nom. nov. is proposed as a replacement name. Additionally, the current work reports another rufous-capped brush finch A. pileatus parasitized by E. atlapetesi in co-infection with an Isospora sp., providing observations of histopathology and phylogenetic analysis of 18S ribosomal RNA (rRNA) gene from E. atlapetesi. Endogenous forms of E. atlapetesi and Isospora sp. were observed in intestinal sections. Few oocysts of Isospora sp. were observed; therefore they were not morphologically or molecularly identified. In return, E. atlapetesi was identified and it was phylogenetically close to Eimeria dispersa Tyzzer, 1929 from the domestic turkey Meleagris gallopavo Linnaeus.

Isospora cardellinae n. sp. (Apicomplexa: Eimeriidae) from the red warbler Cardellina rubra (Swainson) (Passeriformes: Parulidae) in Mexico

A new coccidian species (Protozoa: Apicomplexa: Eimeriidae) collected from the red warbler Cardellina rubra (Swainson) is reported from the Nevado de Toluca National Park, Mexico. Isospora cardellinae n. sp. has subspherical oöcysts, measuring on average 26.6 × 25.4 μm, with smooth, bi-layered wall, c.1.3 μm thick. Micropyle, oöcyst residuum, and polar granule are absent. Sporocysts are ovoidal, measuring on average 19.0 × 12.0 µm, with a knob-like Stieda body, a trapezoidal sub-Stieda body and sporocyst residuum composed of scattered spherules of different sizes. Sporozoites are vermiform with one refractile body and a nucleus. This is the fourth description of an isosporoid coccidian infecting a New World warbler.

Eimeria pileata n. sp. (Apicomplexa: Eimeriidae) from the rufous-capped brush finch Atlapetes pileatus Wagler (Passeriformes: Emberizidae) in Mexico

A new coccidian species (Protista: Apicomplexa: Eimeriidae) collected from the rufous-capped brush finch Atlapetes pileatus Wagler in the Nevado de Toluca Natural Protected Area, Mexico. Oöcysts of Eimeria pileata n. sp. are ellipsoidal, measuring on average 16.5 × 14.1 μm, with a smooth, bi-layered wall. Micropyle and oöcyst residuum are absent, but a polar granule is present. Sporocysts are ellipsoidal, measuring on average 9.0 × 5.4 μm. Stieda and sub-Stieda bodies are both present. A sporocyst residuum is present as a compact mass of granules. This is the third description of an eimeriid coccidian infecting passerines.

Caryospora neofalconis and other enteroparasites in raptors from Mexico

A coprological survey of enteroparasites in raptors (60 Falconiformes) from Central Mexico is reported. Three samples contained coccidian unsporulated oocysts, one contained Eimeria sp., one contained trematode eggs and one contained capillarid and trematode eggs and Eimeria sp. After sporulation at the laboratory, oocysts from a Falco peregrinus were identified as Caryospora neofalconis. The phylogenetic analysis of the C. neofalconis (GenBank accession number KT037081) showed a close relationship to the Australian strain RY 2014 isolate 16710 (GenBank accession number KJ634019) of Caryosporadaceloe, with 99.2% similarity. As far as we are aware, this is the first report of C. neofalconis in raptors from Mexico and the Americas.

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Coprological survey of enteroparasites present in 60 Falconiformes from Central Mexico.

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Caryospora neofalconis identified in one Falco peregrinus.

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First record of C. neofalconis from raptors from Mexico and the Americas.

Histopathological findings in farmed rainbow trout (Oncorhynchus mykiss) naturally infected with 3 different Aeromonas species

This study describes the macroscopic and microscopic lesions in farmed rainbow trout (Oncorhynchus mykiss) naturally infected with genetically identified Aeromonas salmonicida, A. hydrophila, and A. veronii species. The genus Aeromonas includes bacteria that naturally inhabit both waterways and organisms. At least 27 Aeromonas species have been identified to date, some of which can cause significant economic losses in aquaculture. As up to 68.8% of Aeromonas isolates may be misidentified in routine biochemical and phenotypic tests, however, reported cases of Aeromonas infection in fish may be wrongly identified. Our findings confirmed that the 3 Aeromonas species studied are associated with septicemia and dermal lesions in rainbow trout.

Isospora celata n. sp. (Apicomplexa: Eimeriidae) from the orange-crowned warbler Oreothlypis celata (Say) (Passeriformes: Parulidae) in Mexico

A new coccidian species (Protista: Apicomplexa: Eimeriidae) is described from the orange-crowned warbler Oreothlypis celata (Say) collected in the Nevado de Toluca National Park, Mexico at 3,000 metres above sea level. Isospora celata n. sp. has subspheroidal oöcysts, measuring 28.4 × 26.4 μm, with smooth, bi-layered wall c.1.2 μm thick. Micropyle and polar granule are absent, but oöcyst residuum is present as a compact mass. Sporocysts are ovoidal, 18.2 × 12.8 µm. Stieda body knob-like and sub-Stieda body irregular and barely discernible. Sporocyst residuum is composed of granules of different sizes. Sporozoites are vermiform with one refractile body and a nucleus. This is the third description of an isosporoid coccidian infecting a New World warbler.

Molecular characterization of the VP2 gene of infectious pancreatic necrosis virus (IPNV) isolates from Mexico

Infectious pancreatic necrosis virus (IPNV) is one of the most important viruses in the Pacific salmon Oncorhynchus spp., Atlantic Salmon Salmo salar, and Rainbow Trout O. mykiss industry. This virus has been shown to produce high mortality among salmonid fry and juveniles, and survivors might become carriers. Since 2000, IPNV has affected Mexican Rainbow Trout culture, resulting in considerable economic losses. In the current study, molecular characterization of the VP2 gene of a number of Mexican IPNV isolates was done and the virus's phylogenetic relationships to IPNV reference strains were investigated. The phylogenetic analysis indicated that Mexican IPNV isolates are closely related to strains from the United States and Canada and that all Mexican IPNV isolates belong to genogroup 1. Furthermore, low genetic diversity was found between the Mexican isolates (identity, 95.8-99.8% nucleotides and 95.8-99.6% amino acids). The result of the analysis of the amino acid residues found at positions 217, 221, and 247 (alanine, threonine, and glutamic acid, respectively) could be associated with virulence, although the expression of virulence factors is more complex and may be influenced by the agent and host factors. The high percentage of identity among the VP2 genes from geographically distant IPNV isolates and the evidence of wide distribution in the country might have been facilitated by carrier trout. This hypothesis is supported by the identification of the amino acid threonine at position 221 in all Mexican isolates, a factor related to the carrier state for IPNV, as reported by other studies.

Coccidia in passerines from the Nevado de Toluca National Park, Mexico

In this study, we found unsporulated coccidia oocysts in passerines from the Nevado de Toluca National Park, Mexico. We captured birds and took samples of their droppings during three field visits. We examined a total of 72 fecal samples and found unsporulated coccidia oocysts in 10 samples from five passerine species: Atlapetes pileatus (3), Cardelina ruber (1), Mniotilta varia (1), Oreothlypis celata (2) and Regulus calendula (3). This appears to be the first recorded study of unsporulated coccidia oocysts in passerine species from Mexico.

Viral vaccines for bony fish: past, present and future

Since 1970, aquaculture production has grown. In 2010, it had an annual average rate of 6.3% with 59.9 million tons of product and soon could exceed capture fisheries as a source of fishery products. However, the occurrence of viral diseases continues to be a significant limiting factor and its control is important for the development of this sector. In aquaculture farms, fish are reared under intensive culture conditions, and the use of viral vaccines has enabled an increase in production. Several types of vaccines and strategies of vaccination have been developed; however, this approach has not reached the expected goals in the most susceptible stage (fingerlings). Currently, there are inactivated and recombinant commercial vaccines, mainly for salmonids and cyprinids. In addition, updated genomic and proteomic technology has expedited the research and expansion of new vaccine models, such as those comprised of subunits or DNA. The objective of this review is to cover the various types of viral vaccines that have been developed and are available for bony fishes, as well as the advantages and challenges that DNA vaccines present for massive administration in a growing aquaculture, possible risks for the environment, the controversy regarding genetically modified organisms and possible acceptance by consumers.

Isolation and distribution of bacterial flora in farmed rainbow trout from Mexico

Trout farming is a growing aquaculture industry in Mexico, with stock mainly supplied by the importation of eyed eggs. The aim of the present study was to determine the frequency of bacterial isolations in farmed rainbow trout Oncorhynchus mykiss from Mexico. Sixty-five farms distributed among seven states of Mexico were included in the study. Individual samples from gills, liver, spleen, intestine, and kidney were obtained from 563 apparently healthy fish. In total, 371 bacterial isolates were recovered from sampled fish; isolates of the genera Aeromonas, Edwardsiella, Enterobacter, Escherichia, Klebsiella, Plesiomonas, Pseudomonas, and Yersinia were identified. Aeromonads were the most frequently isolated bacteria. Renibacterium salmoninarum was not isolated from any of the sampled fish. Our results showed the presence of bacteria that are potential pathogens of both rainbow trout and humans.

Molecular characterization of the VP1 gene of a Mexican isolate of infectious pancreatic necrosis virus

The presence of infectious pancreatic necrosis virus (IPNV) in salmonids predominantly produces a high mortality rate in first-feeding fry. Genomic analysis of the vp2 gene sequence is most commonly used to determine the genetic diversity of IPNV isolates. Recently, information obtained from the vp1 gene allowed for efficient analysis of the genetic diversity of IPNV. In this study, the vp1 gene from a Mexican IPNV isolate was characterized and compared with IPNV isolates from Europe, North America, and Asia. The results indicate that the Mexican isolate is most closely related genetically to the 2310 strain from Spain.

Development and validation of a short-time cell culture and multiplex reverse transcriptase polymerase chain reaction assay for infectious pancreatic necrosis virus in Mexican farm-sampled rainbow trout

The infectious pancreatic necrosis virus (IPNV) affects several species of freshwater and marine fish. In Mexico, IPNV has an important impact on farming of rainbow trout Oncorhynchus mykiss; however, IPNV distribution in Mexico is unclear. The diagnosis of IPNV is laborious; usually it is based on isolation tests in cell culture followed by immunological identification using techniques of serum neutralization, immunofluorescence, or enzyme-linked immunosorbent assay. It has recently been demonstrated that reverse transcriptase polymerase chain reaction (RT-PCR) is an adequate method for the detection of aquatic birnaviruses. However, its diagnostic use is still limited because very low titers of viable virus cannot be easily detected. In this study, a combination of short-time cell culture and multiplex RT-PCR was established for the diagnosis of IPNV in rainbow trout obtained from farms in the state of Mexico. Three primer sets were used in a single reaction in the multiplex RT-PCR to increase the probability of identifying all serotypes of IPNV serogroup A as well as to help prevent a false-negative result. This approach was able to identify samples with an IPNV concentration of just 0.01 tissue culture infective dose with 50% endpoint (TCID50)/mL, and it identified more infected fish than RT-PCR alone or first-passage cell culture alone. Moreover, this technique made the same identifications as second-passage cell culture but in approximately 30% of the time needed for second-passage cell culture. Consequently, the time and cost efficiency of IPNV diagnosis were greatly reduced.

Hemagglutinating activity of Gallibacterium strains

In the present study, the hemagglutinating activity of seven reference strains, and nine Mexican and three Danish field isolates, of Gallibacterium was investigated by using fresh erythrocytes of 19 different types including chicken (broiler, rooster, layer hen), turkey, pigeon, quail, duck, Harris's hawk (Parabuteo unicinctus), house finch (Carpodacus mexicanus), cow, sheep, horse, dog, rabbit, pig, and human (groups A, B, AB, and O; Rh+). Agglutination was observed for broiler chicken, layer hen, quail, rabbit, and pig erythrocytes with a subset of Gallibacterium strains, whereas most tested strains agglutinated rabbit erythrocytes. Transmission electron microscopic examination of a hemagglutinating strain demonstrated a close interaction between the bacterial and erythrocyte surfaces. The results indicate that some Gallibacterium strains are able to agglutinate avian or mammalian erythrocytes, or both. However, the mechanisms enabling hemagglutination are not known and will be addressed in future studies.

Typing of Haemophilus paragallinarum Strains by Using Enterobacterial Repetitive Intergenic Consensus-Based Polymerase Chain Reaction

The enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) technique was used for fingerprinting of reference strains and Mexican isolates of Haemophilus paragallinarum. A total of nine ERIC patterns were given by the nine serovar reference strains of this bacteria. Two Modesto (C-2) reference strains from different sources showed the same ERIC pattern. Seventeen ERIC patterns were obtained among 29 Mexican isolates included in the study, belonging to serovars prevalent in Mexico (A-1, A-2, B-1, and C-2). Obtained results indicate that the ERIC-PCR technique could be used as a molecular laboratory tool for subtyping of H. paragallinarum.