Retrospective Study of Histomoniasis (Blackhead) in California Turkey Flocks, 2000-2014.

The flagellate parasite Histomonas meleagridis causes a severe disease in turkeys. Since nitarsone, the last antiflagellate feed additive, was withdrawn from the market, H. meleagridis has gained increasing clinical and economic importance, and frequently entire turkey flocks are lost to the disease. Even before the antiflagellate market withdrawal, H. meleagridis has been recognized as a noteworthy disease in commercial turkeys. The aim of this study was to compile and analyze data on histomoniasis outbreaks diagnosed by the California Animal Health and Food Safety System in the years 2000 through 2014 while nitarsone was still available. Sixty-two cases were included in the study. In all cases, the parasite was detected by histopathology. Five cases were from breeder flocks, 44 from commercial meat turkey flocks, and 13 from other flocks such as backyard flocks or pet turkeys. There were between one and eight cases each year with no clear trend over time. Most cases occurred in the warmer months between April and October with a clear peak in August. Turkeys in the flocks with the disease were aged between 2 wk and 15 mo, with a median age of 9 wk. In cases for which mortality was reported, daily mortality ranged between 0.04% and 2% with an average of 0.34% and a median of 0.15%. Five-week mortality in infected houses on three infected ranches was between 1.3% and 68%. In 12 cases, the parasite was observed in organs other than ceca and liver. These included spleen, kidney, bursa of Fabricius, proventriculus, lung, pancreas, and crop. In 58 cases, histomoniasis was considered the most significant and primary diagnosis; in four cases histomoniasis was regarded as an incidental finding. In 14 other outbreaks, detailed information was available. In 11 cases, more than one house on the ranch was affected; in five cases the disease spread to all houses. Total mortality in turkeys from affected flocks ranged between 12% and 65%. In eight flocks, the birds were marketed with a weight that was considered too light. In conclusion, the present study shows that even with nitarsone available as antiflagellate feed, additive histomoniasis was a serious disease of turkeys in the United States with an epidemiology similar to that observed in Europe.

A Novel Mycoplasma sp. Associated with Phallus Disease in Goose Breeders: Pathological and Bacteriological Findings.

In April 2014, poor fertility in a major commercial goose breeder operation in California triggered the submission of six live affected Toulouse ganders ( Anser anser ) to the California Animal Health and Food Safety Laboratory, Turlock branch (University of California-Davis). Toulouse were principally affected among all breeds, and their egg fertility dropped from 65.7% to less than 33.9% in the first 40 days of the 2014 breeding season. The flock consisted of 410 adult birds, 90 males and 320 females, between 2 and 5 yr of age. Inspection of the flock revealed that 44.4% of the Toulouse ganders had severe phallic deformities that prevented them from mating. At postmortem examination, severe yellowish fibrocaseous exudate disrupted the architecture of the phallus and occasionally produced fistulating tracts through the wall of the organ. Microscopically, multifocal lymphoid nodules were noted in the mucosa and submucosa of the phallus and were associated with extensive granulomatous reaction, intralesional bacteria, and spermatozoa. Mycoplasma spp. were isolated from the phallus of affected and nonaffected birds, and PCR protocols targeting the 16S-23S ribosomal RNA intergenic spacer regions and the RNA polymerase beta subunit gene were performed to identify the isolates. Three distinct species were identified on sequencing and analysis using the National Center for Biotechnology Information basic local alignment search tool: Mycoplasma cloacale , Mycoplasma anseris , and an unknown novel Mycoplasma sp. Additionally, Pasteurella multocida , in combination with other bacteria, was also isolated from the phallic lesions and identified as serotype 3 with a DNA profile of 1511 (National Veterinary Service Laboratory). This is the first report of these Mycoplasma spp. and other bacteria associated with reproductive disease in ganders in the United States.

Trichodinosis associated with pathology of the reproductive tract in waterfowl.

Trichodinid ciliophorans are opportunistic parasites of many species of fish, amphibians, and molluscs, but yet never reported in association with lesions in birds. Postmortem and histopathological evaluation of a commercial adult Toulouse gander and female goose, and a wild Mallard drake revealed the presence of severe pathological parasitic colonization of their reproductive tracts. Histopathological findings included moderate to severe granulocytic inflammation, acanthosis, accentuation of the rete pegs, and proliferative hyperplastic squamous metaplasia of the mucosa of the ejaculatory ducts and groove, sulcus spermaticus, glandular part of the phallus (cavum penis), and oviduct in association with large numbers of ciliated protozoa anchored to the tissues or free in the lumen. These protozoa had characteristic morphological features analogous to the family of Trichodinidae. The source of this parasitism could not be determined. To our knowledge, this is the first report of trichodinosis associated with pathology in birds.

Non-Clostridium perfringens infectious agents producing necrotic enteritis-like lesions in poultry.

Necrotic enteritis (NE) produced by Clostridium perfringens is amongst the most prevalent enteric diseases of chickens and turkeys. However, several other bacterial, parasitic and viral agents can cause clinical signs, gross and microscopic lesions in poultry very similar to those of NE and the diseases produced by those agents need to be differentiated from NE. The main differential diagnoses for C. perfringens NE include bacterial (Clostridium colinum, Clostridium sordellii, Clostridium difficile, Pasteurella multocida, Brachyspira spp.), parasitic (Eimeria spp., Histomonas meleagridis) and viral (Duck Herpesvirus type 1, Avian Paramyxovirus type 1) diseases. Confirmation of the diagnosis of these diseases requires identification of the aetiological agents by morphological, cultural and/or molecular methods.

Characterization of Seven Outbreaks of Hemorrhagic Hepatopathy Syndrome in Commercial Pullets Following the Administration of a Salmonella Enteritidis Bacterin in California.

Between April 2013 and April 2015, seven flocks belonging to three different major commercial egg producers inCalifornia experienced a mild increase in mortality 2 to 3 wk after administration of Salmonella Enteritidis bacterins. Strains of chickens involved were H&N (flock A1, A2, B2, C1, C2, and C3) and Lohmann white (flock B1). Vaccination was administered individually through injection either in the breast muscles or subcutis in the legs between 11 and 18 wk of age in all flocks. Clinical signs ranged from inapparent to lameness, reluctance to walk, greenish diarrhea, and retching-like symptoms. The mortality ranged from 0.16% to 1.38% per week, with the highest peaks occurring usually 2 to 3 wk postvaccination, and then declined rapidly. Postmortem examinations revealed enlarged livers with disseminated hemorrhages and pale foci of necrosis. Also, severe extensive hemorrhages in the intestine, heart, and proventriculus were observed in a few birds. Various degrees of productive, exudative giant cell granulomatous myositis were observed invading deeply the muscles and subcutis at the site of vaccination. The myositis was always associated with optically empty vacuoles positive for neutral lipids by Oil Red O stain. Droplets of Oil Red O material were also noticed in the affected livers and intestines. Congo red stain highlighted the presence of amyloid in moderate to severe amounts in the breast muscles and moderate amounts in livers, spleens, and intestines. Salmonella antigens were detected in the injection sites and livers by immunohistochemical staining. No viruses or toxic substances were recovered from the liver, spleen, intestine, and pectoral muscles, and the few bacteria isolated were interpreted as secondary postmortem invaders. In addition, livers and bile tested for hepatitis E virus were negative by reverse-transcriptase polymerase chain reaction.

Spatial and temporal epidemiology of infectious laryngotracheitis in central California: 2000-2012.

In October of 2005 an outbreak of a vaccine-like strain of infectious laryngotracheitis (ILT), indistinguishable from the chicken embryo origin (CEO)-like vaccine strains, was detected by routine passive surveillance in the Central Valley of California, U. S. A. In response, a highly coordinated industry effort by two companies led to a significant decrease in the incidence of ILT over the same geographic region between 2008-2012. In order to understand the geographic and temporal spread of ILT in California before and after the outbreak, Global Information Systems (GIS) mapping coupled with spatial, temporal, and spatial- temporal statistics were used to identify retrospective and prospective low-rate clustering (i.e., less ILT than statistically expected) and high-rate clustering (i.e., more ILT than statistically expected) of ILT spatially and temporally. Results showed two high-rate retrospective spatial-temporal clusters and one low-rate prospective spatial-temporal cluster which were all statistically significant (P < 0.05). Overall, spatial-temporal clustering accounted for 36.9% of the positive ILT cases, while temporal clustering and spatial clustering done separately each accounted for 0% of the ILT cases, respectively. This demonstrates the utility of combining spatial and temporal clustering for ILT surveillance. Due to the risk of reversion to virulence and spread to immunologically naive broilers, future application of the CEO-based vaccine in the identified high rate spatial-temporal clusters should be avoided and other vaccine alternatives considered in order to avoid repeat outbreaks in those areas. This should especially be followed during the winter months of December, January, and February, which were found to have the highest prevalence of ILT (P < 0.05). Analysis of GIS data within the high-rate clusters showed that wind direction and farm density were minor factors in the spread of ILT. Shared roads may have played a role in the spread of ILT in one of the two high rate spatial-temporal clusters.

Atypical distribution of fowl pox lesions in broilers.

An unusual cutaneous fowl pox outbreak occurred in 8-wk-old broilers in California. Rounded and longitudinal, proliferative scratch-associated lesions were found only in feathered areas of the body. Both sides of the hip, the lower abdomen, pericloacal area, and lateral lower neck area were involved. The head, legs, feet, and toes did not have lesions. Birds in only one section of one of five houses were affected. Fifteen percent condemnations occurred in birds from the affected house due to the skin lesions. A diagnosis of fowl pox was achieved by histopathology, viral isolation, and direct electron microscopy. The unusual distribution of pox lesions was assumed to be associated with skin scratches. There was no evidence that mosquitoes or other types of insects were involved in this outbreak. To the knowledge of the authors, this is the first report of this kind of unusual fowl pox in the United States.