Campylobacter infection of commercial poultry.

Campylobacter jejuni, a widespread food-borne pathogen is responsible for enteritis in the populations of both industrialised and developing nations and is acquired by consumption of contaminated water, milk and food products. Contaminated poultry meat is regarded as an important source of campylobacteriosis, with both commercial broiler and turkey growing flocks infected at two to three weeks of age by direct and indirect horizontal exposure. Non-chlorinated water is regarded as a vehicle of infection, followed by rapid intraflock dissemination. Intensification in the poultry industry has contributed to the increased prevalence rates on carcasses associated with increased stocking density and mechanized processing which are inherent to the high efficiency dictated by a competitive market. Currently, pre- and post-harvest control measures may ameliorate the problem of Campylobacter infection in consumers. Refrigerated storage and transport of red meat and poultry, appropriate handling and food preparation, and thorough cooking reduce the possibility of food-borne infection. In view of the world-wide distribution of C. jejuni infection and the multiplicity of sources, including non-pasteurised milk and contaminated water, it is inappropriate to impose trade restrictions on poultry meat based on the detection of campylobacters.

Preliminary findings of Salmonella spp. in captive green iguanas (Iguana iguana) and their environment.

Captive reptiles are routinely identified as reservoirs of Salmonella spp. and reports of reptile-associated salmonellosis are increasing. Unfortunately, little is known about the epidemiology of Salmonella spp. and green iguanas. We did a limited survey of a green-iguana farm in El Salvador to identify sources of Salmonella spp. in green iguanas and their environment. A limited number of samples for microbiological culture were collected from iguanas (adult, hatchling, and embryos) and their environment (food, water, soil, shelter, insects, and wild-caught lizards). Salmonella spp. was isolated from the intestine of both adult (3/20) and hatchling iguanas (8/20). There was no evidence of Salmonella spp. in the reproductive tracts of female iguanas (0/10). Salmonella spp. was isolated from the surface of 40% (7/16) of the egg surfaces tested. Salmonella spp. was not identified from the externalized yolk-sac of the iguana embryos tested. Soil samples from a breeding pen and a nest were both positive for Salmonella spp. Eight different Salmonella spp. serotypes were identified in this survey. These results suggest that horizontal transmission of Salmonella spp. is a potential source of exposure to hatchling iguanas at this facility.

Geographic information systems and the environmental risk of schistosomiasis in Bahia, Brazil.

A geographic information system was constructed using maps of regional environmental features, Schistosoma mansoni prevalence in 30 representative municipalities, and snail distribution in Bahia, Brazil to study the spatial and temporal dynamics of infection and to identify environmental factors that influence the distribution of schistosomiasis. Results indicate that population density and the duration of annual dry period are the most important determinants of prevalence of schistosomiasis in the areas selected for study. Maximum rainfall, total precipitation during three consecutive months, annual maximum or minimum temperatures, and diurnal temperature difference were not shown to be significant factors influencing S. mansoni prevalence in local populations or distribution of snail hosts. Prevalence of the disease was highest in the coastal areas of the state. Higher prevalence tended to occur in areas with latossolo soil type and transitional vegetation.

Evaluation of alternative strategies to prevent Newcastle disease in Cambodia.

Velogenic viscerotropic Newcastle disease (vvNCD), which is endemic in Cambodia, can be prevented in theory by a combination of biosecurity and immunization of broiler flocks. The relative contribution of appropriate biosecurity and effective vaccination was quantified at the farm level, applying realistic projections for capital investment, fixed and variable production costs and losses following infection. Non-protected broiler flocks generate a loss when the probability of vvNCD infection exceeds 0.4. Applying both biosecurity and effective vaccination would sustain profitability up to a probability of exposure of 1.0. The benefit to cost ratios for alternative strategies were evaluated for a range of probabilities of exposure to vvNCD extending from 0.1 to 1.0. The benefit-to-cost ratio for biosecurity exceeded unity at a risk of exposure exceeding 0.1, and 0.2 for vaccination and the combination of vaccination and biosecurity respectively. A sensitivity analysis demonstrated that the efficiency of protection, feed cost, and financial consequences of infection markedly affected the projected benefit-to-cost ratios associated with alternative methods of prevention.

Infectious diseases and parasites of ratites.

This article discusses infectious and parasitic disease conditions in the three ratite species. Diseases and parasitic conditions are reviewed in relation to etiology, transmission, pathology, diagnosis, treatment, and prevention. To ensure optimum reproduction and growth of birds on large production units, a veterinarian must understand management in relation to biosecurity and disease problems.

Jurisprudence for ratite practitioners.

Veterinarians are frequently confronted with medico-legal issues relating to certification, malpractice and the responsibilities of owners and managers. This article reviews relevant principles to guide practitioners.

Intracellular Campylobacter-like organisms associated with rectal prolapse and proliferative enteroproctitis in emus (Dromaius novaehollandiae).

Rectal prolapse was the presenting clinical finding in a group of juvenile emus (Dromaius novaehollandiae). Gross findings included severely thickened and rugose distal rectal mucosae. Histologically, there were thickened villi, enterocyte hyperplasia, dilated glands filled with mucus and heterophils, and a dense infiltrate of heterophils, macrophages, lymphocytes, and plasma cells in the lamina propria. Examination of Warthin-Starry silver-stained sections revealed numerous apically located comma-shaped intracytoplasmic bacteria approximately 1 x 3 microns in size. Campylobacter-like organisms morphologically compatible with ileal symbiont intracellularis now known as Lawsonia intracellularis were seen via electron microscopy. Bacteria were further characterized by indirect immunofluorescence using monoclonal antibody specific for the 25-27-kd outer membrane protein of L. intracellularis.

Comparison of procedures to detect Chlamydia psittaci antibodies in cockatiels (Nymphicus hollandicus).

Diagnostic serologic procedures for psittacine chlamydiosis were evaluated using experimentally inoculated cockatiels (Nymphicus hollandicus). Chlamydia psittaci was recovered from subjects on day 16 postinoculation. Seroconversion was confirmed by the direct complement fixation (DCF) test. The blocking enzyme-linked immunosorbent assay was demonstrated to be the most sensitive of three serodiagnostic procedures evaluated from inoculation until day 24 postinfection, with 92% sensitivity and 73% specificity. The DCF test was progressively more sensitive over the duration of the experiment, attaining 100% sensitivity and specificity on the day 24 postinfection. This study confirms the ability of the DCF procedure to adequately detect C. psittaci antibodies. Limitations relating to reproducibility of serologic results under clinical conditions found in this study indicate that a further refinement of tests is required to consistently detect and quantify antibodies.

Husbandry practices as related to infectious and parasitic diseases of farmed ratites.

Over the past decade, there has been a world-wide increase in the number of farm-raised ratites. The focus of ostrich production remains in South Africa, but other countries are initiating production of this bird in addition to the emu and rhea. Ostriches, emus and rheas are being produced commercially outside their native habitat, resulting in new and unique disease presentations. The authors describe bacterial, viral and parasitic diseases which are emerging in production settings. Biosecurity, together with adequate management and nutrition, will reduce the likelihood of flock exposure and limit mortality in the event of infection. The problem currently facing the industry is that most ratite facilities do not incorporate separate quarantine areas. Newly-introduced birds may contaminate soil and facilities with pathogens such as Mycobacterium spp. and Salmonella spp. Ratites have excellent production potential if producers can profitably multiply and rear healthy stock. The authors discuss the currently-known diseases which may affect the viability of an intensive production facility.

Characteristics of animals adopted from an animal control center whose owners complied with a spaying/neutering program.

A study of 137 cats and 567 dogs received by and subsequently adopted from an animal control center was performed to determine characteristics of animals whose new owners subsequently complied with a prepaid spaying/neutering program. Four times as many dogs as cats were adopted. Females were adopted more frequently than males. Owners who adopted female cats were most likely to comply with the prepaid spaying/neutering program, followed, in order, by owners of male cats, owners of female dogs, and owners of male dogs. Most animals returned to the shelter were < 4 months old. Dogs suspected to be of mixed breeding that were > 4 months old were most likely to be adopted. Owners who adopted a female dog suspected to be of mixed breeding were more likely to have the dog spayed than were owners who adopted a female dog that appeared purebred.

Tuberculosis in commercial emus (Dromaius novaehollandiae).

Extensive granuloma formation typical of tuberculosis was observed in a mature female emu. The diagnosis was confirmed by demonstration of acid-fast bacilli in lesions and culture of a Mycobacterium with growth characteristics resembling M. avium from liver tissue. Individual emus on the affected farm and an epidemiologically related unit gave a positive skin reaction to intradermal M. avium tuberculin. The implication of tuberculosis in commercial emus is noted in relation to the growth of the industry in North America and to management and commercial practices that encourage dissemination of infection within the species and to other exotic and domestic animals.

Eastern equine encephalitis in a flock of emus (Dromaius novaehollandiae).

Eastern equine encephalitis (EEE) was diagnosed in a flock of emus in southeastern Louisiana. The outbreak involved juvenile and adult breeders ranging in age from 20 to 36 months, with an attack rate of 76% and a case fatality rate of 87%. The diagnosis was confirmed by isolation and characterization of the viral agent, and by detection of EEE antibody in two recovered emus. High mortality was preceded by marked depression, hemorrhagic diarrhea, and emesis of blood-stained ingesta. On postmortem examination, hemorrhagic enteritis and multiple petechia of viscera were observed. Microscopic changes included severe necrosis of hepatocytes, intestinal mucosa, and necrotizing vasculitis of the spleen and lamina propria of the intestine. No nervous system lesions were observed. This outbreak occurred concurrently with EEE in horses and was attributed to unseasonably heavy rainfall with an abundance of arthropod vectors and proximity to free-living reservoir host species.

The significance of Campylobacter jejuni infection in poultry: a review.

Campylobacter is a significant cause of enterocolitis in consumers of undercooked poultry meat. Campylobacter jejuni is the most significant of the three thermophilic Campylobacter species, and is responsible for intestinal colonization in poultry and food-borne enteritis in humans. Generally, C. jejuni is apathogenic in poultry, although newly hatched chicks and turkeys may develop a transient diarrhoea following infection. Modern intensive poultry production favours the introduction of infection into commercial growing units, resulting in intestinal colonization during the second to fourth weeks inclusive. Routes of infection include contaminated fomites, infected water supply, rodents, insects, and free-living birds. Vertical transmission is considered unlikely. Contamination of poultry meat is enhanced by deficiencies in transport and processing of broilers and turkeys. Scalding, defeathering and evisceration represent the significant points of cross-contamination during processing. Epidemiological correlation has been established between consumption of contaminated chicken and outbreaks of human campylobacteriosis. Amelioration of infection by application of improved standards of hygiene and decontamination is possible in the context of commercial poultry production. Improvement in washing of carcasses, and the application of chemical disinfectants and gamma irradiation have the potential to reduce the prevalence of C. jejuni contamination in poultry meat. These innovations, together with improved storage and handling of meat products, will reduce the risk of campylobacteriosis to consumers.

Avian paramyxoviruses from migrating and resident ducks in coastal Louisiana.

Cloacal and tracheal swabs were collected from 1,409 hunter-killed ducks in Cameron Parish, Louisiana, during the 1986 and 1987 waterfowl seasons. Thirty avian paramyxoviruses (PMV's) were isolated from 605 blue-winged teal (Anas discors), 75 mottled ducks (A. fulvigula), 375 gadwalls (A. strepera), 334 green-winged teal (A. crecca), and 20 mallards (A. platyrhynchos). Prevalence of PMV decreased (P = 0.042) from September (4%) through November (2%) to December and January (1%). Juveniles had a higher prevalence of PMV (P less than 0.0001) than adults. An isolate from resident mottled ducks documents transmission of PMV's on the coastal wintering areas of Louisiana. The four serotypes isolated, PMV-1, PMV-4, PMV-6, and PMV-8, were typical of PMV's commonly associated with free-living waterfowl.

A model of Staphylococcus aureus bacteremia, septic arthritis, and osteomyelitis in chickens.

We studied the occurrence, magnitude, and kinetics of bacteremia and the resultant osteomyelitis and septic arthritis in an avian model of Staphylococcus aureus infection. Thirty-day-old male broiler chicks were inoculated i.v. with 10(5), 10(6), or 10(7) cfu of strain Duntravis, a beta-hemolytic, coagulase-producing, capsular type 8 isolate from the synovial fluid of a 2-year-old black boy. Bacteremia occurred in 80%, 90%, and 100% of animals inoculated with 10(5), 10(6), or 10(7) cfu, respectively. The magnitude of bacteremia in surviving, bacteremic animals increased for 96 hours after inoculation and then decreased after a plateau phase. Osteomyelitis and septic arthritis occurred only in chicks that were continuously bacteremic. The occurrence of osteomyelitis was uniform among continuously bacteremic animals and developed 1 to 23 hours after inoculation. Chickens are susceptible to systemic infections with S. aureus. Bacteremia, osteomyelitis, and septic arthritis may be induced in healthy chickens without prior manipulations that depress their resistance.

Salmonella colonization in commercial pet turtles (Pseudemys scripta elegans).

An epidemiological survey was conducted on two commercial turtle farms in southern Louisiana to determine the reason for an apparent increase in the prevalence of Salmonella spp. in turtle hatchlings at the time of pre-export certification examination. Pond water was consistently found to be contaminated (6/36 samples) with either Salmonella newport, S. arizonae, or S. poona. Environmental specimens obtained from eggs and turtle hatcheries (204 specimens) failed to yield Salmonella spp. A sample comprising 197 hatchlings, derived from a batch previously demonstrated to be contaminated, showed a salmonella prevalence of 12%, with S. arizonae and S. poona the only serotypes isolated. Four serotypes of Salmonella sp. isolated by a certifying laboratory in 1988, and 20 salmonella isolates obtained from hatchling turtles, were all resistant to gentamicin. The emergence of gentamicin resistance in Salmonella spp. isolated from turtles will reduce the effectiveness of preventive measures in use in Louisiana since 1984.