Outbreak of avian mycobacteriosis in a flock of two-year-old domestic pigeons (Columba livia f. domestica)

This report describes an outbreak of avian mycobacteriosis in a flock of 100 two-yr-old pigeons. Over a 6-mo period, the sick pigeons showed cachexia followed by death. In Columbiformes classic tubercles rarely develop, but in these affected pigeons granulomatous nodular lesions of various sizes, containing numerous acid-fast bacilli, were found in the internal organs. The lesions were observed in the liver, spleen, intestine, bone marrow, ovary, and oviduct. Despite their breeding age, atrophy was also found in the ovary and oviduct. Microorganisms belonging to Mycobacterium avium complex were identified in the affected tissues by polymerase chain reaction.     

Unusual biphasic disease in domestic pigeons (Columba livia f. domestica) following experimental infection with Sarcocystis calchasi

A novel Sarcocystis species has recently been reported in the domestic pigeon (Columba livia f. domestica) as intermediate host, causing severe central nervous signs similar to Paramyxovirus-1 or Salmonella Typhimurium var. cop. infection. Transmission of the parasite via the northern goshawk (Accipiter gentilis) as definitive host has been established. Experimental infection of domestic pigeons with sporocysts excreted by experimentally infected northern goshawks reproduced the natural infection in the pigeon, proving the causative role of the parasite in the disease. Here, we describe in greater detail the course of the fulminant biphasic disease depending on the infectious dose. Pigeons infected with 10(3) or 10(4) sporocysts showed clinical signs of polyuria and apathy around 10-11 days postinfection (dpi) and sudden neurological signs 51-57 dpi as a second phase of disease. Pigeons infected with higher doses died within 7-12 dpi, also showing polyuria and apathy but without nervous signs. At necropsy, livers and spleens had multifocal necroses and infestations with parasitic stages, namely, schizonts. Moreover, lesions and schizonts were also found in the lung, bone marrow, and next to blood vessels in the connective tissue of various organs. Pigeons infected with 102 sporocysts remained symptomless until 58-65 dpi, when sudden central nervous signs occurred. Major histopathologic findings of pigeons with neurological signs were encephalitis and myositis of virtually every skeletal muscle with high infestations of sarcocysts. Only mild myocarditis and very few cysts were found in the heart muscles. Importantly, a sentinel pigeon developed identical lesions when compared to those of low-dose infected pigeons, suggesting a risk of mechanical transmission of sporocysts from freshly infected to uninfected pigeons in a flock. By contrast, chickens failed to develop any clinical signs or pathologic lesions in the same experiment. The findings further characterize the new highly pathogenic disease in domestic pigeons, which clinically mimics paramyxovirosis and salmonellosis in both phases of the disease and exclude chickens as further intermediate host species.     

Evaluation of antibiotics for racing pigeons (Columba livia var. domestica) available in The Netherlands

Antibiotics and chemotherapeutics marketed for use in racing pigeons (Columba livia var. domestica) were evaluated by comparing the dosages and indications given by the manufacturers with the data obtained by pharmacokinetic, bacteriological and efficacy studies. This comparison showed that only three of the recommended dosages and indications of the 60 formulations marketed in The Netherlands are scientifically sound and in accordance with the literature. It is to be expected that the majority of the antimicrobials for pigeons will not satisfy the requirements for final registration as a pigeon therapeutic under the Dutch Veterinary Medicines Act of 1985. Several factors affecting drug availability are discussed, such as the different routes of administration and the influence of food. The public health aspects of the consumption of medicated pigeons is also discussed. Although there is no legislation with regard to this subject, a recommended withdrawal time of 10 days for the majority of the antimicrobials seems advisable.     

Physiological and hormonal aspects in female domestic pigeons (Columba livia) associated with breeding stage and experience

The present study examined the changes in serum biochemical values, hormone profiles and ovary prolactin receptor (PRLR) gene expression occurring in female domestic pigeons (Columba livia) under different breeding status and experience. The egg‐laying pigeons had lower calcium, total protein, albumin, prolactin levels and higher oestrogen levels than those of incubating birds (p < 0.05). First‐time breeders had higher (p < 0.05) progesterone levels and lower (p < 0.05) prolactin levels than that of experienced ones. The levels of oestrogen and follicle‐stimulating hormone (FSH) increased with age (p < 0.05). The very old birds showed a pronounced increase (p < 0.05) in PRL, FSH and progesterone and a little decrease in oestrogen. Serum prolactin level was not correlated with the ovary PRLR mRNA expression pattern among all the pigeons. Results showed that serum physiological profile of female pigeons was correlated with breeding status, whereas reproductive hormone levels were correlated with advancing breeding experience. It was concluded that female pigeons had a good ability of recovering from nutrient loss after each breeding attempts, and the degradation of reproductive performance might be attributed to changes in the endocrine system.     

Experimental inoculation of pigeons (Columba livia) with Mycobacterium bovis

The purpose of this pilot study was to determine if pigeons (Columba livia) are susceptible to infection with Mycobacterium bovis by either oral or intratracheal inoculation and to assess their possible role in the lateral transmission of bovine tuberculosis. Six pigeons were orally inoculated with 1.3 x 10(5) colony-forming units of M. bovis, six pigeons were intratracheally inoculated with the same dose, and six pigeons served as noninoculated controls. The study continued for 90 days postinoculation (PI), with groups of birds necropsied at 30-day intervals, and fecal samples and tissues were collected for mycobacterial culture. Two pigeons, one intratracheally inoculated and one orally inoculated, shed M. bovis in their feces at 1 day PI, and one intratracheally inoculated bird shed M. bovis in its feces 60 days PI. Whereas no illness or weight loss was present during the course of the study, 2 of 12 inoculated birds exhibited microscopic lesions of mycobacteriosis, and the organism was isolated from tissues of three inoculated birds. Pigeons are susceptible to infection with M. bovis after high dose inoculation and can shed the organism in their feces for up to 60 days PI; intratracheally inoculated birds appear more likely to become active fecal shedders of M. bovis. Although these were high dose inoculations under experimental conditions, pigeons may potentially play a role in the lateral transmission of bovine tuberculosis between infected and uninfected mammalian hosts.     

Evaluation of anthelmintics, antiprotozoal drugs and ectoparasiticides for racing pigeons (Columba livia var. domestica) available in The Netherlands

Anthelmintics, antiprotozoal drugs and ectoparasiticides specially marketed for use in racing pigeons (Columba livia var. domestica) were evaluated by comparing dosages and indications given by the producers with data obtained from efficacy studies or empirical data. Of a total of 63 products, 59% were in accordance with the literature. Fifty-nine percent of the dosages and indications of anthelmintics were in accordance with scientifically obtained data, while for trichomonacides, coccidiostats and ectoparasiticides the figures were 47%, 59% and 100% respectively. Public health aspects of the consumption of medicated pigeons are discussed.     

Seroprevalence of Toxoplasma gondii and Chlamydia psittaci in domestic pigeons (Columbia livia domestica) at Sebele, Gaborone, Botswana

High antibody titres to Toxoplasma gondii and Chlamydophila psittaci were demonstrated in serum collected from domestic pigeons at average titres of 1:128 and 1:64 respectively. The public health implications of these findings are discussed.     

Screening for several potential pathogens in feral pigeons (Columba livia) in Madrid

Background

Pathogens with the zoonotic potential to infect humans, such as Campylobacter jejuni, Campylobacter coli and Chlamydophila psittaci, can be found in feral pigeons (Columba livia). Given the high density of these birds in the public parks and gardens of most cities, they may pose a direct threat to public health.

Methods

A total of 118 pigeons were captured in three samplings carried out in 2006-2007 in public parks and gardens in Madrid, Spain. Standard haematological and morphological analyses were carried out on the pigeons. PCR was used to screen for the presence of Campylobacter jejuni, C. coli and Chlamydophila psittaci. Positive samples were confirmed by DNA sequencing.

Results

The analyses demonstrated a high prevalence of Chlamydophila psittaci (52.6%) and Campylobacter jejuni (69.1%) among the birds captured. In contrast, Campylobacter coli was rarely detected (1.1%).

Conclusions

Pigeons in Madrid can carry Chlamydophila psittaci and Campylobacter jejuni. They may be asymptomatic or subclinical carriers of both pathogens.     

The influence of stress from transport and handling on hematologic and clinical chemistry blood parameters of racing pigeons (Columba livia domestica)

In the present study, the influence of stress from handling and transport on some frequently examined blood parameters of racing pigeons was evaluated. After 3 hr, there was a highly significant (P < 0.01) increase in the number as well as in the percentage of heterophils and decrease of lymphocytes. In clinical chemistries, increases of creatine kinase and glucose and a decrease of uric acid were observed. There was a mean decrease of the total white blood count of >15% that was less significant (P < 0.05). Changes in lactate dehydrogenase, basophils, and monocytes did not prove to be significant; eosinophils, aspartate aminotransferase, total protein, and the packed cell volume were not influenced by stress.     

An outbreak of encephalitis in pigeons (Columba livia) in the Canary Islands (Spain)

An encephalitic disease in pigeons, characterized by paralysis of extremities, torticollis, head tremor, and diarrhea, is described. The negative titers in the hemagglutination tests, the presence of Feulgen-positive intranuclear inclusions in the cells of the granular layer of the cerebellum and the fibroblast culture, and the presence of viral particles with an icosahedral-herpetic morphology and a diameter of 100-170 nm all indicate that the etiology of this outbreak may be related to the encephalitis caused by herpesvirus, at present diagnosed only in Iraq and some African countries.     

In vitro nitroimidazole resistance of Trichomonas gallinae and successful therapy with an increased dosage of ronidazole in racing pigeons (Columba livia domestica)

Six out of eight different Trichomonas gallinae strains isolated from racing pigeons proved to be resistant to the nitroimidazole drugs ronidazole, carnidazole and metronidazole. The minimal cytocidal concentration of ronidazole was determined in in vitro experiments. Moreover, a therapeutic dose for ronidazole was determined for the control of trichomoniasis in pigeons from which the resistant T. gallinae strains were isolated. It was a 5-fold increase of the recommended ronidazole dosage which eliminated the infection in affected pigeons.     

Antitrichomonal activity of Peganum harmala alkaloid extract against trichomoniasis in pigeon (Columba livia domestica)

1. This study was designed to evaluate the antitrichomonal effects of P. harmala alkaloid extract against T. gallinae, both in vitro and in vivo, as well as comparing it to that of metronidazole, conventional antitrichomonal medication and harmine and harmaline, the two alkaloids present in P. harmala.

2. T. gallinae were collected by the wet mount method from infected free-living pigeons. The in vitro assay was performed using multi-well plates containing test compounds in final concentrations of 5, 10, 15, 20, 30, 50 or 100 μg/ml. The in vivo assay was done on 60 experimentally infected pigeons dosed with metronidazole at 50 mg/kg body weight (BW) or alkaloids at 25 mg/kg BW.

3. The 24 h minimum inhibitory concentration (MIC) of alkaloid extract was 15 µg/ml while that of metronidazole was 50 µg/ml. Harmine and harmaline revealed 24 h MIC of 30 and 100 µg/ml, respectively. Treatment of infected pigeons with alkaloids led to a full recovery after 3 d but with metronidazole total eradication of trophozoites was not achieved.

4. In conclusion, data of the present study suggested P. harmala is a potent natural anti-trichomonal agent, effective against T. gallinae.     

Toxoplasma gondii antibodies in common barn-owls (Tyto alba) and pigeons (Columba livia) in New Jersey

In southwestern New Jersey during 1986 and 1987, common barn-owls and pigeons were captured on farmsteads and tested for Toxoplasma gondii antibodies by a modified direct agglutination test. In 1986, 3/28 (10.7%) adult and 0/124 nestling owls tested positive at titers of greater than or equal to 1:40. Additionally, 2/34 (5.9%) pigeons tested had T. gondii antibodies at titer of 1:320. In 1987, 9/38 (27.3%) adult and 18/80 (22.5%) nestling owls tested positive at titers of greater than or equal to 1:25; this includes 3/38 (7.9%) adult and 1/80 (1.3%) nestling owls that tested positive at a titer of 1:50.     

Short restraint time does not influence markers of serum oxidative stress in homing pigeons (Columba livia)

Restraint in a confined space, such as a cage or a box, may be perceived by birds as a stressful condition. Some concern has been expressed about restraining homing pigeons (Columba livia) in transport crates for sport or for scientific research. Therefore, this study sought to test whether short restraint time in a transport crate for 1, 2 or 18 (overnight) h causes oxidative stress in homing pigeons and whether it is more stressful than flying. To isolate the effect of crowding from that of transport per se, the pigeons were kept in an immobile crate, that is, without any movement. To quantify oxidative stress, we measured serum levels of oxidative damage (ROMs) and of antioxidant capacity (OXY). We found that pigeons restrained in transport crates showed no significant variation for both markers of oxidative stress, regardless of the duration of restraint. Conversely, pigeons which had flown around 200 km had increased levels of oxidative damage and decreased levels of serum OXY, both clear manifestations of oxidative stress. These results suggest that maintaining homing pigeons in transport crates for a short time (i.e. 1–18 h) does not cause oxidative stress.     

Differential expression of fatty acid transporters and fatty acid synthesis-related genes in crop tissues of male and female pigeons (Columba livia domestica) during incubation and chick rearing

1. The growth performance of squabs reared solely by male or female parent pigeons was measured, and the changes of lipid content of crop milk and the expression profiles of genes potentially involved in lipid accumulation by crop tissues of parent pigeons were evaluated during incubation and chick rearing.

2. Squabs increased in body weight during 25 d of rearing, whereas both male and female pigeons lost weight after finishing rearing chicks, and the weight loss of male pigeons was significantly greater than that of female parent pigeons. Lipid content of crop milk from both parent pigeons gradually decreased to the crude fat level in the formulated diet after 10 d (R10) of chick rearing.

3. The gene expression of fatty acid translocase (FAT/CD36), fatty acid-binding protein 5 (EFABP) and acyl-CoA-binding protein (ACBP) in male pigeon crop tissue were the greatest at 17 d (I17) of incubation. In female pigeons, FAT/CD36 expression was the highest at I14, and both EFABP and ACBP expression peaked at I14 and R7. The expression of acetyl-CoA carboxylase and fatty acid synthase in male pigeons reached the maximum level at R1, while they peaked at I14 and I17, respectively in female pigeons. The gene expression of peroxisome proliferators-activated receptor-gamma (PPARγ) was the greatest at I17 in the male, while it was at I14 in the female. However, no regular changing pattern was found in PPARα gene expression in male pigeons.

4. These results indicated that male and female pigeons may make different contributions in rearing squabs. The gene expression study suggested that fatty acids used in lipid biosynthesis of crop milk probably originated from both exogenous supply and de novo synthesis. The sex of the parent pigeon affected the lipid content of crop milk and the expression profiles of genes involved in fatty acid transportation and lipogenesis.     

Investigations on the influence of selected compulsory measures on clinically relevant haematological and blood-chemical parameters of racing pigeons (Columba livia f. dom.)

In the presented study the influence of stress and environmental factors on selected haematological and blood-chemical parameters in racing pigeons was examined. Blood was taken at three defined days and haematological as well as blood-chemical parameters of clinical relevance were determined. In comparison to reference values published for pigeons, the majority of the values obtained in this study were within physiological borders. The daily handling of the pigeons did not have any significant effect on the examined parameters. Also the heterophile/lymphocyte ratio did not show any changes characteristic of a stress reaction. In contrast, after change of the housing dies with pigeons originating normally from a flock, the first blood sampling should be performed after a 4 or 5-day lasting period of acclimatisation to the the individual housing conditions.     

Echocardiographic examinations in unsedated racing pigeons (Columbia livia forma domestica) with special consideration for the physical training

The heart of the bird is characterized by its enormous efficiency. Racing pigeons are bred for a long time for their flight performance. In the present study therefore the heart of 108 racing pigeons of the breed Bricoux were examined by means of echocardiography. The birds were either kept in aviaries (untrained) or as racing birds. The aim was to find out whether differences in the heart dimensions and/or the heart work occur between untrained and trained birds, like it is described already in humans and mammals (so-called athletic's heart). Significant differences between the two groups could be determined with different parameters, in particular with parameters, which affect the heart work. Thus it was for the first time possible to prove the formation of a athletic's heart in birds, and by that the adaptation of the avian heart to appropriate performance requirements.