Mapping the poultry insectome in and around broiler breeder pullet farms identifies new potential Dipteran vectors of Histomonas meleagridis.

BACKGROUND: Histomonas meleagridis can infect chickens and turkeys. It uses the eggs of the cecal worm Heterakis gallinarum as a vector and reservoir. Litter beetles (Alphitobius diaperinus) and other arthropod species have been implicated as potential vectors, but little information about other arthropod species as potential vectors is known. METHODS: Four broiler breeder pullet farms were sampled every 4 months. On each farm, three types of traps were set inside and outside two houses. Trapped arthropod specimens were morphologically identified at order level and grouped into families/types when possible. Selected specimens from abundant types found both inside and outside barns were screened for H. meleagridis and H. gallinarum by qPCR. RESULTS: A total of 4743 arthropod specimens were trapped. The three most frequently encountered orders were Diptera (38%), Coleoptera (17%), and Hymenoptera (7%). Three hundred seventeen discrete types were differentiated. More arthropods were trapped outside than inside. Alpha diversity was greater outside than inside but not significantly influenced by season. The composition of the arthropod populations, including the insectome, varied significantly between trap location and seasons. Up to 50% of litter beetles tested positive for H. meleagridis DNA 4 months after an observed histomonosis outbreak. Sporadically litter beetles were positive for H. gallinarum DNA. Thirteen further arthropod types were tested, and specimens of four Dipteran families tested positive for either one or both parasites. CONCLUSIONS: This study describes the insectome in and around broiler breeder pullet farms and identifies new potential vectors of H. meleagridis through qPCR. The results show a limited but present potential of arthropods, especially flies, to transmit histomonosis between farms.

A Survey of Coccidia and Nematodes in Pastured Poultry in the State of Georgia.

The aim of this study was to evaluate and quantify the parasitological challenge in pastured poultry production in the state of Georgia. Over the course of 1 yr, fecal samples from six turkey flocks, 10 broiler flocks, and 13 layer flocks were collected on a pastured farm in 2-wk intervals to determine counts of Eimeria oocysts and nematode eggs. Average coccidia counts were 10,198 oocysts per gram of feces (OPG) in broiler flocks, 1470 OPG in layer flocks, and 695 OPG in turkey flocks. The means in broiler and turkey flocks were higher at their first week on pasture. Counts in broilers and layers were significantly higher in spring than in winter and summer. Coccidia counts in broilers were lower than published numbers in conventionally reared poultry, indicating the rotation system of the pastures might effectively reduce the infection pressure. Next-generation sequencing of PCR products showed the presence of most described Eimeria spp. in broilers, layers, and turkeys. In addition, operational taxonomic units (OTUs) x, y, and z were found. The frequency of species was similar for broilers and layers, with the exception that Eimeria praecox and OTU z were more common in layers. In layer flocks, the average count of roundworm eggs per gram of feces (EPG) was 509 EPG with 80% of the samples being positive. The mean counts had no clear pattern related to age. There was an increase of EPG with the increase of temperatures during spring and summer with the peak at midfall. Worm eggs from laying hens were identified as Ascaridia galli. The seasonal differences suggest that higher temperatures might result in an increase of egg survival and sporulation in the environment.

Artículo regular­Muestreo de coccidias y nematodos en aves en pastoreo en el estado de Georgia El objetivo de este estudio fue evaluar y cuantificar el desafío parasitológico en la producción avícola en pastoreo en el estado de Georgia. En el transcurso de un año, se recolectaron muestras fecales de seis parvadas de pavos, 10 parvadas de pollos de engorde y 13 parvadas de gallinas de postura en una granja de pastoreo en intervalos de dos semanas para determinar los conteos de ooquistes de Eimeria y huevos de nematodos. Los recuentos promedio de coccidias fueron 10,198 ooquistes por gramo de heces (OPG) en parvadas de pollos de engorde, 1470 ooquistes por gramo de heces en parvadas ponedoras y 695 ooquistes por gramo de heces en parvadas de pavos. Los promedios en las parvadas de pollos de engorde y pavos fueron más altos en su primera semana en pastoreo. Los conteos en pollos de engorde y ponedoras fueron significativamente más altos en primavera que en invierno y verano. Los recuentos de coccidios en pollos de engorde fueron más bajos que los números publicados en aves criadas de manera convencional, lo que indica que el sistema de rotación de pastizales podría reducir efectivamente la presión de infección. La secuenciación de próxima generación de los productos de PCR mostró la presencia de la mayoría de las especies de Eimeria spp descritas en pollos de engorde, gallinas de postura y pavos. Además, se encontraron unidades taxonómicas operativas (OTU) x, y, z. La frecuencia de especies fue similar para pollos de engorde y gallinas de postura, con la excepción de que Eimeria praecox y las unidades taxonómicas operativas z fueron más comunes en gallinas de postura. En las parvadas de gallinas de postura, el recuento promedio de huevos de helmintos intestinales por gramo de heces (EPG) fue de 509 EPG, con el 80% de las muestras positivas. Los recuentos medios no tenían un patrón claro relacionado con la edad. Hubo un aumento de huevos de helmintos intestinales por gramo de heces con el aumento de las temperaturas durante la primavera y el verano con el pico a la mitad del otoño. Los huevos de helmintos de las gallinas de postura se identificaron como Ascaridia galli. Las diferencias estacionales sugieren que las temperaturas más altas podrían resultar en un aumento de la supervivencia de los huevos y su esporulación en el medio ambiente.

Heterakis gallinarum and Histomonas meleagridis DNA persists in chicken houses years after depopulation.

The poultry pathogen Histomonas meleagridis is transmitted by chicken cecal worms (Heterakis gallinarum) and is potentially transmitted by second order insect vectors and paratenic hosts. Darkling beetles (Alphitobius diaperinus) are poultry farm pests that infest barns. An outstanding question is the degree to which darkling beetles transmit both Heterakis and Histomonas. In this study we monitored populations of darkling beetles and assessed their positivity for both Heterakis and Histomonas by PCR. Uniquely, this study was conducted during the scheduled deconstruction of Auburn University's Poultry Research Farm. Therefore, we were able to monitor beetle and litter infection status months and years after bird depopulation. The duration of our monitoring continued through three seasons. We show that environmental DNA from both Heterakis and Histomonas persist in the environment long after prior infections, even in the absence of living Heterakis and its hosts. Finally, in an intensive search for live Heterakis, we discovered reniform nematodes (plant parasitic nematodes) residing in the soil floor of poultry farms.