Mark A. Goodwin

Transmission of Eimeria, Viruses, and Bacteria to Chicks: Darkling Beetles (Alphitobius diaperinus) as Vectors of Pathogens

Abstract Darkling beetle homogenates (DBH) were prepared from beetles collected from seven premises (farms). DBH were shown to contain myriad infectious organisms including bacteria (e.g., Salmonella), viruses (e.g., reovirus), and Eimeria (the causative agents of intestinal coccidiosis). The present study establishes the fact that darkling beetles serve as vectors for common avian pathogens. Darkling beetles must be considered on a list of other vectors known to transmit common poultry pathogens. The risk posed by beetles with respect to dissemination of diseases is of immense importance to the poultry industry. The possibility of severe adverse economic impact as a result of these diseases should not be overlooked or casually dismissed.

Use of Aviguard and Other Intestinal Bioproducts in Experimental Clostridium perfringens-associated Necrotizing Enteritis in Broiler Chickens

Clostridium perfringens-associated necrotic enteritis (CPANE) is a common problem among rapidly growing broiler strains of chickens that are raised intensively in modern microenvironments. The purpose of this study was to compare the use of Aviguard and three other intestinal bioproducts (two normal gut flora [NGF] products and one probiotic product) in experimental CPANE in broiler chickens. Male broiler chicks were housed in the same environmentally controlled facility and given one of six treatments. The necrotic enteritis infection model (NEIM) used in the present study was effective in inducing CPANE intestinal gross lesions in broiler chickens. Equally important, Aviguard was found to be significantly more effective than either the other two NGF products or the probiotic for reducing gross lesions induced by the NEIM. In addition, Aviguard/NEIM-treated chicks ate more feed and had better feed efficiency than their NGF- or probiotic/NEIM-treated counterparts. Other significant differences among these four reconstituted microbial preparations were not found. Results from this study have additional importance because they further support the use of reconstituted microbial preparations as novel and effective alternatives to antibiotics that can reduce the severity of C. perfringens-associated necrotic enteritis challenge in broilers.

Leukocyte changes associated with acute inflammation in chickens.

Leukocyte changes in chickens with turpentine-induced inflammation were investigated sequentially at 0, 6, 12, and 24 hours and at 2, 3, 4, 7, and 14 days. During acute inflammation, significant leukocytosis and heterophilia developed by 6 hours and persisted through 7 days. The peak mean heterophil and leukocyte counts occurred at 12 hours and 3 days, respectively. Left shifts were present at 12 and 24 hours as detected by 100-cell leukocyte differential counts. Heterophil mean nuclear scores documented nuclear hyposegmentation (left shift) during early inflammation and nuclear hypersegmentation (right shift) during convalescence. Mean monocyte and lymphocyte counts peaked at 2 and 3 days, respectively. Basophil and eosinophil counts were erratic. Toxic changes of heterophils were most apparent during intense left shifts and consisted of cell swelling, degranulation, cytoplasmic vacuolation, and cytoplasmic basophilia. Cytoplasmic basophilia was the last aspect of toxic change to resolve. Ultrastructurally, toxic heterophils had intracellular edema, dissolution of granules, retention of ribosomes, nuclear membrane blebs, and decreased heterochromatin density. All inflammation-associated alterations in cell counts and morphology returned to baseline values and appearance by 14 days after turpentine administration.

Immunosuppression and Intracellular Calcium Signaling in Splenocytes from Chicks Infected with Chicken Anemia Virus, CL-1 Isolate

Hematocrits, histopathology, concanavalin A-induced lymphocyte proliferation, intracellular calcium signaling, and lymphocyte subpopulations were analyzed over a 6-week period in individual chicks inoculated with the CL-1 isolate of chicken anemia virus. Lymphoid depletion/atrophy was present in the thymus and bone marrow by 11 days post-infection (PI). Anemia was present at 14 days PI. The mean lymphocyte proliferation stimulation index (SI) of the inoculated group was significantly lower than that of the control group at 11 days PI. This response was reversed at 18 days PI, when the SI of the inoculated group was significantly higher than that of the controls; values subsequently returned to baseline. The increase in intracellular calcium levels in CAV-infected chicks and controls paralleled the proliferative response. Percentages of CD3-, CD4-, CD8-, and natural-killer-positive-staining cells decreased significantly at 18 and 25 days PI. The most dramatic decrease occurred in the CD8-positive-staining cell population at 18 and 25 days PI.

Diarrhea associated with intestinal cryptosporidiosis in turkeys

Turkey poults were suffering from diarrhea on a farm in which several previous grow-outs of turkeys had experienced a clinically identical problem. Upon necropsy, significant gross lesions were restricted to the gastrointestinal tract. Segments of small intestine were pale and distended with cloudy mucoid material and a few gas bubbles. The ceca contained fluid and gas. Fresh organ portions were collected and fixed in 10% neutral buffered formalin and submitted for histological processing and examination (light microscopy and scanning and transmission electron microscopy). Small (2-4 micron) basophilic bodies identified as Cryptosporidium sp. were present in enterocytes of the middle and lower small intestine. The villi were moderately atrophic, the crypts were hypertrophic, and the lamina propria was infiltrated by large numbers of lymphocytes, heterophils, and fewer macrophages and plasma cells. Numerous intraepithelial leukocytes and exocytosing inflammatory cells also were present.

Quantitation of intestinal D-xylose absorption in normal and reovirus-inoculated turkeys.

A micromethod was modified to quantitate intestinal D-xylose absorption in young and extremely small birds. This test was performed in control and cloned-reovirus-inoculated turkey poults to investigate intestinal absorptive function. Absorption peaks and curves for control poults closely resembled those observed in normal humans. Poult groups absorbed significantly less D-xylose at 24 and 72 hours (P less than 0.0001 and P less than 0.0008, respectively) but not at 120 hours (P = 0.3178) after receiving a single oral dose of cloned reovirus. The modified D-xylose absorption test is suitable for experimental and clinical determination of absorptive function of the small intestine in the fowl.

Respiratory coccidiosis (Cryptosporidium baileyi) among northern Georgia broilers in one company.

Cryptosporidium baileyi causes respiratory disease in chickens. The purposes of this prospective study were to determine the incidence of C. baileyi tracheitis among broilers in a commercial setting, and the relationship between C. baileyi tracheitis and production performance parameters. All samples came from 56 farms that grow broilers for one company in northern Georgia. Tracheas were collected and examined with a light microscope and cultured for viruses and bacteria. Overall, 23 of 56 (41%) broiler flocks had C. baileyi tracheitis. Parasitism rates among C. baileyi-infected flocks ranged from a low of 10% to a high of 60%. Cryptosporidium baileyi tracheitis was very highly correlated (rho = 0.81, n = 56, P < 0.00001) to severity of tracheitis, negatively correlated (rho = -0.27, n = 56, P < 0.04) with average body weight, and correlated with airsacculitis (rho = 0.30, n = 56, P < 0.03) and condemnations (rho = 0.27, n = 56, P < 0.05). The present study indicates that C. baileyi infection rates are high, and the role that this parasite plays in the pathogenesis of respiratory disease and production losses could be unexpectedly large.

Lack of Correlation Between Microscopic Lesion Scores and Gross Lesion Scores in Commercially Grown Broilers Examined for Small Intestinal Eimeria spp. Coccidiosis

Comparisons were made between microscopic lesion scores (MLSs) and gross lesion scores (GLSs) in sections from small intestine of broilers during three routine coccidiosis screenings. The duodenal and jejunal GLS were determined and recorded by different evaluators. During each screening, 2-cm sections of duodenum and jejunum were collected, and sections of intestine were then scored using a microscopic lesion scoring system. No correlation between MLS and GLS was observed in duodenum in two out of three coccidiosis screenings, and no correlation was observed between MLS and GLS in jejunum in three out of three screenings. Our findings demonstrate that, if used alone in coccidiosis screening, GLSs can underestimate infections and may not provide a true representation of the magnitude of Eimeria maxima infection within broiler flocks.

Effect of Poultry Litter Treatment? (PLT?) on Death Due to Ascites in Broilers

The purposes of this study were to determine the effect of Poultry Litter Treatment (PLT) on levels of litter moisture, litter nitrogen, atmospheric ammonia, and death due to ascites. Data were collected from chicks raised in containment conditions that resembled commercial settings. The ascites death rate (5.9%) in broiler chicks on PLT-treated litter was significantly (chi 2 = 15.5, df = 1, P = 0.0001) lower than that (31.5%) in broiler chicks raised on untreated litter. Likewise, atmospheric ammonia levels in pens that had been treated with PLT were significantly (P < 0.05) lower than those in pens that received no treatment. Under the conditions of the present study, litter moisture and litter nitrogen levels were not different (P > 0.05) among treatments at any sample interval.

Multisystemic Adenovirus Infection in Broiler Chicks with Hypoglycemia and Spiking Mortality

The search for a solitary cause of spiking mortality (so-called spiking mortality syndrome [SMS]) among broiler chicks has been thwarted by the fact that many agents will cause similar mortality histograms. Recently, severe hypoglycemia has been said to be a characteristic finding in chicks that die with SMS. In the present case study, we report adenovirus inclusions in the pancreas, small intestines, and liver of chicks with hypoglycemia and spiking mortality. We attributed the hypoglycemia and mortality to hepatic insufficiency.