One dead 6-wk-old male racing pigeon (Columba livia) was submitted for postmortem evaluation after presenting with weight loss, anorexia, dry shanks, dehydration, and lethargy. The bird belonged to a confined flock with 12 other pigeons raised by a hobbyist. Two pigeons in the flock reportedly had died with a history of similar clinical signs. On gross examination, the liver and the spleen were diffusely dark brown to black. Histopathology revealed moderate to large amounts of anisotropic, intracytoplasmic black pigment, compatible with hemozoin, in the spleen, liver, lung, and kidneys, with small amounts in the heart and meninges of the brain. Marked plasmacytic infiltrates were observed in liver, lungs, heart, and kidneys. Blood smears from a clinically affected concomitant pigeon from the flock revealed numerous light-blue, round to oval, intraerythrocytic trophozoites and meronts suggestive of Plasmodium spp. PCR and sequencing tests were performed from spleen and ceca with fragments of the 18S ribosomal RNA and the mitochondrial cytochrome b (cytB) genes. Sequencing results confirmed the presence of Plasmodium in the affected pigeon. Although an exact genetic match could not be determined, the most similar species to the isolate from this study are Plasmodium relictum, Plasmodium matutinum, Plasmodium lutzi, and Plasmodium homocircumflexum.

The 2014 outbreak of clade 2.3.4.4A highly pathogenic avian influenza (HPAI) led to the culling of millions of commercial chickens and turkeys and death of various wild bird species. In this outbreak, older chickens and turkeys were commonly infected, and succumbed to clinical disease compared to younger aged birds such chicken broilers. Some experimental studies using waterfowl species have shown age-related differences in susceptibility to clinical disease with HPAI viruses. Here, we evaluate differences in H5 Hemagglutinin (HA) tissue binding across age groups, using recombinant H5 HA (rHA) proteins generated using gene sequences from low pathogenic (A/mallard/MN/410/2000(H5N2 (LPAIV)) and a HPAIV (A/Northern pintail/Washington/40964/2014(H5N2)) influenza A virus (IAV). Respiratory and intestinal tracts from chickens, ducks (Mallard, Pekin, Muscovy) and turkeys of different age groups were used to detect rHA binding with protein histochemistry, which was quantified as the median area of binding (MAB) used for statistical analysis. There were species and tissue specific differences in the rHA binding among the age groups; however, turkeys had significant differences in the HPAIV rHA binding in the respiratory tract, with younger turkeys having higher levels of binding in the lung compared to the older group. In addition, in the intestinal tract, younger turkeys had higher levels of binding compared to the older birds. Using LPAIV, similar species and tissues, specific differences were seen among the age groups; however, only turkeys had overall significant differences in the respiratory tract MAB, with the older birds having higher levels of binding compared to the younger group. No age-related differences were seen in the overall intestinal tract rHA binding. Age-related differences in rHA binding of the LPAIV and HPAIV demonstrated in this study may partially, but not completely, explain differences in host susceptibility to infection observed during avian influenza outbreaks and in experimental infection studies.

Reporte de caso- Virus de la bronquitis infecciosa Variante de California CA1737 aislada de una parvada comercial de ponedoras con oviductos quísticos y mala calidad externa del huevo. El síndrome de la falsa capa es una condición en la cual el tracto reproductivo de las gallinas está infectado con cepas del virus de la bronquitis infecciosa (IBV) que causan daño permanente al oviducto. Posteriormente, estas gallinas desarrollan oviductos quísticos y bajas en la postura de huevo, las parvadas afectadas no alcanzan los picos de producción de huevos esperados. El laboratorio de Salud Animal y Seguridad Alimentaria de California, con sede en Turlock, recibió cuatro casos separados de una parvada comercial de ponedoras ISA Brown de 25 a 28 semanas de edad. Las aves se enviaron para evaluación diagnóstica debido a una producción de huevos subóptima y por presencia de picoteo en las cloacas. Se recibieron un total de 31 aves y consistieron en aves de postura vivas, mortalidad reciente y además una charola de huevos. No se observaron signos clínicos en las aves vivas enviadas. Los hallazgos macroscópicos más comunes incluyeron oviductos izquierdos quísticos, signos de picoteo en las cloacas, regresión ovárica y celomitis de la yema. Los huevos tenían una forma anormal con depósitos irregulares, blancos y arenosos en la superficie de la cáscara. Microscópicamente, había atrofia de los oviductos, hipoplasia glandular y salpingitis linfocítica. Además, se observó traqueítis linfoplasmocítica y túbulos renales dilatados con áreas multifocales de mineralización. El virus de la bronquitis infecciosa se identificó mediante PCR cuantitativa de transcripción inversa a partir de grupos de tejidos de tonsilas cecales y muestras agrupadas de hisopos traqueales. La secuenciación de la región hipervariable S1 de IBV y la secuenciación de IBV del genoma completo fueron homólogas en un 97 % a la variante de California CA1737/04. La prueba definitiva de las anomalías reproductivas causantes de la cepa CA1737 requerirá estudios de desafío con el cumplimiento de los postulados de Koch y la evaluación de los factores de riesgo y de confusión. Key words: infectious bronchitis virus, cystic oviducts, California, CA1737

Transmissible viral proventriculitis (TVP) and chicken proventricular necrosis virus (CPNV) affect the broiler industry globally and are emerging diseases of economic importance. Here, we present the findings of TVP from processed broiler carcasses in Argentina following marked condemnation at the processing plant. We studied a total of 122 abnormally presenting proventriculi at processing from 42-to-50-day-old, male Cobb500^™ broiler chicken carcasses from 11 farms belonging to the same company in 13 episodes of proventriculi–gizzards condemnation between December 2021 and April 2022. The proventriculi were enlarged and pale with a widened gastric isthmus. A histopathologic lesion score system was developed based on the presence of a combination of key microscopic findings, the distribution, and the severity of the lesions. Scoring of the affected proventriculi revealed 65% (79/122) with a score of 4, 23% (28/122) with a score of 3, and 12% (15/122) with a score of 2. Focal to multifocal immunoreactivity against the VP2-CPNV antigen within the necrotic glandular epithelial cells was noted in the affected proventriculi using immunohistochemistry. We found 84.4% (103/122) of the studied proventriculi with TVP lesions grossly and microscopically scored were positive for CPNV by RT-PCR. The sequencing results of the PCR product showed a high nucleotide sequence similarity (88.97%) to previously published VP1-CPNV sequences. We confirmed CPNV infection in most of the TVP affected proventriculi in all condemnation episodes at a broiler chicken processing plant in Argentina during the studied period. This study documents TVP associated with CPNV detection at processing plants in Argentina for the first time.

Ascaridia nymphii is a roundworm species affecting domestic avian species, initially described in 2015. One pen-reared, 4-year-old, female American Show Racer pigeon (Columba livia f. domestica) was submitted to the California Animal Health and Food Safety Laboratory System (CAHFS) Turlock branch, University of California–Davis, for postmortem examination and diagnostic work-up. Grossly, large numbers of ascarids were in the lumen of the proventriculus, gizzard, and duodenum, and a small number was present in the lumen of the trachea, esophagus, and crop. A focal, coiled adult nematode was embedded in the hepatic parenchyma. Ascarids were tan and measured approximately 3.5–4.5 cm in length. The liver was moderately enlarged, green-tinged, and had small, firm, and off-white scattered nodules. Microscopically, we observed multifocal to coalescing granulomas containing intralesional nematodes delineated by necrotic debris, multinucleated giant cells, eosinophilic and heterophilic inflammation, hemorrhage, and bacterial colonies in the liver. The genotypic characterization of the Ascaridia sp. in our case (GenBank database accession PX488893) shared 100% identity with A. nymphii isolated from the intestinal tract of a cockatiel (Nymphicus hollandicus) from Japan in 2015 (GenBank database accession LC057210.1) based on PCR and sequence analysis of an 815 bp segment of the 18S rRNA gene. This report describes the accidental A. nymphii infection, which caused severe gastrointestinal impaction and hepatic migration in a domestic pigeon.

Reporte de caso- Detección diagnóstica de influenza aviar de baja patogenicidad H7N3 en una parvada comercial de aves de caza. Se diagnosticó influenza aviar de baja patogenicidad (LPAI) H7N3 en una parvada de gallinas reproductoras de codornices japonesas criadas comercialmente. Las aves se recibieron con una historia inicial de caída en la producción de huevo y excrementos acuosos. La prueba inicial de PCR para influenza aviar de la parvada fue negativa; sin embargo, la mortalidad comenzó a aumentar drásticamente, lo que generó posteriores evaluaciones y el envío de más aves al laboratorio de diagnóstico. En el examen ante mortem, las aves estaban letárgicas, con las plumas erizadas y tenían dificultad para respirar. El examen macroscópico reveló mala condición corporal, deshidratación moderada, esplenomegalia, regresión ovárica y aerosaculitis. Varias gallinas produjeron huevos con cascarón delgado o sin cascarón. Microscópicamente, se observaron encefalitis linfoplasmocítica con necrosis de células neuronales, neumonía fibrinoheterófila y depleción linfoide esplénica con depósito de amiloide. El virus de influenza aviar se detectó en un caso de seguimiento y se caracterizó como de baja patogenicidad subtipo H7N3. Las codornices son una especie de interés en la patobiología de los virus de la influenza aviar, subrayada por la capacidad de servir como huésped de amplificación.