OBJECTIVE:The present study assessed the added diagnostic value of histopathology in complementing molecular detection of World Organization for Animal Health-listed viral pathogens during Colombia's national shrimp health surveillance program. METHODS:Pooled samples of pleopods from 1,470 whiteleg shrimp Penaeus vannamei (5 animals/pool for a total of 294 pooled samples) were screened for white spot syndrome virus, Taura syndrome virus, and yellow head virus using standardized PCR/reverse transcription PCR assays in accordance with Instituto Colombiano Agropecuario protocols. A subset of 81 shrimp was taken for whole-body histopathology analysis following standardized protocols and a semiquantitative G0-G4 lesion grading scale. Lesions were classified by organ system, and histopathological findings were compared to molecular results. RESULTS:All PCR assays were negative, with internal and external controls performing as expected. Using histopathology, lesions were identified in 77% of the shrimp examined, and lesions were primarily mild. Frequent findings included integumentary and gill colonization by Zoothamnium spp.; hepatopancreatic tubular necrosis with hemocytic granuloma-like reactions compatible with bacterial infection; intranuclear inclusion-like bodies, possibly of parvoviral origin; and focal myofiber necrosis, with organisms consistent with microsporidia. Autolysis was common but did not preclude lesion interpretation. CONCLUSIONS:Histopathology provided diagnostic information that was not captured by targeted molecular assays, revealing subclinical, opportunistic, and nonviral processes relevant to shrimp health. Incorporating histopathology into routine surveillance programs enhances pathogen detection and strengthens health assessments to certify disease-free status of shrimp production systems, as recommended by the World Organization for Animal Health.
Hexachaeta cundiboyacensis Rodriguez, a new species of the colombiana species group is described and illustrated. In addition, the first biological information on host plants and natural enemies for the colombiana species group is provided. Host plants include: Aegiphila alba Moldenke (Lamiaceae) for H. colombiana Lima and Aegiphila integrifolia (Jacq.) B.D. Jacks. (Lamiaceae) for the new species described here. The wasp Opius (Bellopius) hexachaeta Kula and Aguirre (Braconidae) was found parasitizing the new species. A modification of the species key of Hernández-Ortiz (1999) to incorporate this new species is also presented.
In the Americas, transgenic crops producing insecticidal proteins from Bacillus thuringiensis Berliner (Bt, Bacillales: Bacillaceae) have been used widely to manage fall armyworm (FAW, Spodoptera frugiperda [J.E. Smith]). As resistance to Cry1 single-gene Bt maize (Zea mays L.) rapidly evolved in some FAW populations, pyramided Bt maize hybrids producing Cry1, Cry2, or Vip3Aa proteins were introduced in the 2010s. We examined field-evolved resistance to single- and dual-protein Bt maize hybrids in 2 locations in southeastern Brazil, where plant damage by FAW larvae far exceeded the economic threshold in 2017. We collected late-instar larvae in Cry1A.105 + Cry2Ab and Cry1F maize fields and established 2 FAW populations in the laboratory. The F1 offspring reared on the foliage of Bt and non-Bt maize plants (Cry1A.105 + Cry2Ab and Cry1F) showed neonate-to-adult survival rates as high as 70% for both populations. There was no significant difference in the life-table parameters of armyworms reared on non-Bt and Bt maize foliage, indicating complete resistance to Cry1A.105 + Cry2Ab maize. Larval survival rates of reciprocal crosses of a susceptible laboratory strain and the field-collected populations indicated nonrecessive resistance to Cry1F and a recessive resistance to Cry1A.105 + Cry2Ab maize. When relaxing the selection pressure, the armyworm fitness varied on Cry1A.105 + Cry2Ab and non-Bt maize; the resistance was somewhat stable across 12 generations, without strong fitness costs, although one of the lines died confounded by a depleted-quality, artificial rearing diet. To our knowledge, this is the first report documenting the practical resistance of FAW to a pyramided Bt crop. We discuss the implications for resistance management.
Positive animal welfare (PAW) is a relatively recent idea that emphasizes the good experiences to improve the mental state. The objective of this review was, describe the indicators used in bovine welfare protocols, identify the domains considered, and establish a proposal focused on indicators to assess positive welfare. It was identified that the protocols require excessive evaluation times, qualify by granting a single score and do not allow regional adaptations according to the critical conditions that may exist in different countries. Furthermore, the main focus of the existing protocols is on the first 3 domains (nutrition, physical environment and health), leaving the recording of the behavior and the mental state of the animals to a lesser degree of importance. A series of indicators were specified, which would promote positive well-being, related to the domains of physical environment and behavioral interactions, emphasizing comfort, environmental, social, sensory, and nutritional enrichment. In conclusion including the diagnosis of the mental state of animals in a comprehensive way is necessary to identify shortcomings and propose improvements that contribute to improving the quality of life of animals.
Se determinó el comportamiento de FHIA-20 y FHIA-23 a Mycosphaerella fijiensis y M. musicola. El estudio se realizó en una casa de malla en la granja Montelindo de la Universidad de Caldas, a 1010 msnm, temperatura media de 22.8 °C, precipitación anual de 2200 mm, humedad relativa del 76%. Se inoculó conidias de Paracercospora fijiensis y Pseudocercospora musae, y la combinación de ambos, en plántulas entre cuatro y seis hojas. Se evaluó período de incubación (PI), tiempos de evolución de síntomas (TES) y desarrollo de las enfermedades (TDE), además, número de lesiones por hoja (NLH). En FHIA-20, P. musae, P. fijiensis y P. musae + P. fijiensis tuvieron un PI más largo que en Dominico Hartón, superior en 3, 20 y 10 días, respectivamente; así mismo, el TES de las sigatokas amarilla y negra y la combinación de ambas, fue más prolongado en FHIA-20, en 5, 49 y 26 días que en el material local, respectivamente. En FHIA-23, P. musae, P. fijiensis y P. musae + P. fijiensis presentaron 2, 6 y 3 días más de PI, respectivamente, que en Gros Michel; además, FHIA-23 presentó un TDE de las sigatokas amarilla y negra y la combinación de ambas, superiores a Gros Michel en 9, 16 y 11 días, respectivamente; comportándose FHIA-20 altamente resistente y tolerante a las sigatokas negra y amarilla, respectivamente, y FHIA-23 resistente.
