Gallinae Infection Research Articles

Selection of a suitable reference gene for gene-expression studies in Trichomonas gallinae under various biotic and abiotic stress conditions

Trichomonas gallinae, a globally distributed protozoan parasite, significantly affects the pigeon-breeding industry. T. gallinae infection mainly causes yellow ulcerative nodules on the upper respiratory tract and crop mucosa of pigeons, impeding normal breathing and feeding and ultimately causing death. Real-time quantitative PCR (qPCR) is a crucial technique for gene-expression analysis in molecular biology. Reference-gene selection for normalization is critical for ensuring this technique’s accuracy. However, no systematic screening or validation of T. gallinae reference genes has been reported. This study quantified the transcript levels of ten candidate reference genes in T. gallinae isolates with different genotypes and culture conditions using qPCR. Using the geNorm, NormFinder, and BestKeeper algorithms, we assessed these reference genes’ stabilities and ranked them using RankAggreg analysis. The most stable reference gene was tubulin beta chain (TUBB), while the widely used reference genes TUBG and GAPDH demonstrated poor stability. Additionally, we evaluated these candidate reference genes’ stabilities using the T. gallinae TgaAtg8 gene. On using TUBB as a reference gene, TgaAtg8′s expression profiles in T. gallinae isolates with different genotypes remained relatively consistent under various culture conditions. Conversely, using ACTB as a reference gene distorted the data. These findings provide valuable reference-gene-selection guidance for functional gene research and gene-expression analysis in T. gallinae.

Evidence for strain-specific virulence of Trichomonas gallinae in African columbiformes.

Infection by parasites or pathogens can have marked physiological impacts on individuals. In birds, infection may affect moult and feather growth, which is an energetically demanding time in the annual cycle. Previous work has suggested a potential link between clinically visible Trichomonas gallinae infection and wing length in turtle doves Streptopelia turtur arriving on breeding grounds. First, T. gallinae infection was characterized in 149 columbids from 5 species, sampled on turtle dove wintering grounds in Senegal during the moulting period, testing whether infection by T. gallinae is linked to moult. Trichomonas gallinae prevalence was 100%, so rather than testing for differences between infected and uninfected birds, we tested for differences in moult progression between birds infected by different T. gallinae strains. Twelve strains of T. gallinae were characterized at the internal transcribed spacer 1 (ITS1)/5.8S/ITS2 region, of which 6 were newly identified within this study. In turtle doves only, evidence for differences in wing length by strain was found, with birds infected by strain Tcl-1 having wings nearly 6 mm longer than those infected with strain GEO. No evidence was found for an effect of strain identity within species on moult progression, but comparisons between infected and uninfected birds should be further investigated in species where prevalence is lower.

Trichomonas gallinae induces heterophil extracellular trap formation in pigeons.

Avian trichomonosis is a worldwide and cross-species epidemic, and the infection in pigeons is particularly severe. Although the disease causes a serious threat to poultry health resulting in significant economic losses, the relationship between Trichomonas gallinae (T. gallinae) and host innate immunity is still not clear. Extracellular traps (ETs) are an innate immunity response to parasitic infections. However, whether host cells can produce ETs after T. gallinae infection has not yet been reported. In the present study, the ability of T. gallinae to induce the production of heterophil extracellular traps (HETs) in pigeons was examined. T. gallinae-induced HETs were observed by scanning electron microscopy (SEM) and the main components of HETs were detected by fluorescence confocal microscopy. Changes in reactive oxygen species (ROS) and lactate dehydrogenase (LDH) were tested during the HETosis. A quantitative analysis of T. gallinae-induced HETs, the role of myeloperoxidase (MPO), store-operated Ca (2+) entry (SOCE), and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in T. gallinae-induced HET formation were conducted by inhibitor assays. The results showed that T. gallinae induced ET formation in pigeon heterophils. ETs consisted of a DNA skeleton, neutrophil elastase (NE), MPO, and Histone3 (H3). T. gallinae-induced HETs formation in a dose- and time-dependent process. The release of T. gallinae-induced HETs depends on MPO, SOCE, and NADPH oxidase. Furthermore, after T. gallinae stimulated pigeon heterophils, ROS production was significantly increased, while no significant differences in the LDH activity were observed.

Captive Breeding and Trichomonas gallinae Alter the Oral Microbiome of Bonelli’s Eagle Chicks

Bonelli’s eagle (Aquila fasciata) is an endangered raptor species in Europe, and trichomonosis is one of the menaces affecting chicks at nest. In this paper, we attempt to describe the oral microbiome of Bonelli’s eagle nestlings and evaluate the influence of several factors, such as captivity breeding, Trichomonas gallinae infection, and the presence of lesions at the oropharynx. The core oral microbiome of Bonelli’s eagle is composed of Firmicutes, Bacteroidota, Fusobacteria and Proteobacteria as the most abundant phyla, and Megamonas and Bacteroides as the most abundant genera. None of the factors analysed showed a significant influence on alfa diversity, but beta diversity was affected for some of them. Captivity breeding exerted a high influence on the composition of the oral microbiome, with significant differences in the four most abundant phyla, with a relative increase of Proteobacteria and a decrease of the other three phyla in comparison with chicks bred at nest. Some genera were more abundant in captivity bred chicks, such as Escherichia-Shigella, Enterococcus, Lactobacillus, Corynebacterium, Clostridium and Staphylococcus, while Bacteroides, Oceanivirga, Peptostreptococcus, Gemella, Veillonella, Mycoplasma, Suttonella, Alloscardovia, Varibaculum and Campylobacter were more abundant in nest raised chicks. T. gallinae infection slightly influenced the composition of the microbiome, but chicks displaying trichomonosis lesions had a higher relative abundance of Bacteroides and Gemella, being the last one an opportunistic pathogen of abscess complications in humans. Raptor’s microbiomes are scarcely studied. This is the first study on the factors that influence the oral microbiome of Bonelli’s eagle.

Incidence of gastrointestinal parasites in pigeons with an assessment of the nematocidal activity of chitosan nanoparticles against Ascaridia columbae

In this investigation, the incidence and intensity of gastrointestinal parasites of domestic pigeons were evaluated, additionally, in vitro and in vivo evaluation of the antiparasitic activity of chitosan nanoparticles against the most predominant gut parasite. Therefore, 240 domestic pigeons (160 adults and 80 squabs) obtained from different localities in Giza governorate, Egypt, from February to July 2021, were subjected to parasitological and postmortem examination. The results revealed that 97% of pigeons were vulnerable to single or mixed gastrointestinal parasites. The detected helminths were identified as Capillaria columbae (C. columbae) with a total incidence of (12.5%), Ascaridia columbae (A. columbae) (83.3.%), Heterakis gallinarum (H. gallinarum) (18.7%), Raillietina cesticillus (R. cesticillus) (7.5%), Raillietina echinobothrida (R. echinobothrida) (29%), Choanotaenia infundibulum (C. infundibulum) (22.9%), Davainea proglottina (D. proglottina) (26.6%), and Cotugnia proglottina (C. proglottina) (14.5%). At the same time, the identified protozoan parasites were Trichomonas gallinae (T. gallinae), and Eimeria columbae (E. columbae), with a total incidence of 25 and 79%, respectively. Helminths and Eimeria infections were higher in adults than squabs, while T. gallinae infection was reported with a higher incidence in squabs (62.5%) than adults (6.2%). From our findings, A. columbae was the most predominant gut parasite in the examined pigeons. Thus, it was subjected to in vitro and in vivo treatment with chitosan nanoparticles. Serum and tissue samples were collected from the birds which have been used in the in vitro study to evaluate the oxidative stress markers as malondialdehyde (MDA), Nitric oxide levels and Tumor Necrosis Factor-alpha (TNF-α) and Interleukin-1β activity also, chitosan nanoparticles- treated worm ultrastructure were determined using scanning electron microscopy (SEM). Finally, we recommend periodic monitoring of pigeon's farm to detect the parasitic infestation, and from our results, we recommend chitosan nanoparticles as a potent nematocidal agent.

Transcriptome Analysis Revealed Potential Mechanisms of Resistance to Trichomoniasis gallinae Infection in Pigeon (Columba livia).

Trichomoniasis gallinae (T. gallinae) is one of the most pathogenic parasites in pigeon, particularly in squabs. Oral cavity is the main site for the host-parasite interaction. Herein, we used RNA-sequencing technology to characterize lncRNA and mRNA profiles and compared transcriptomic dynamics of squabs, including four susceptible birds (S) from infected group, four tolerant birds (T) without parasites after T. gallinae infection, and three birds from uninfected group (N), to understand molecular mechanisms underlying host resistance to this parasite. We identified 29,809 putative lncRNAs and characterized their genomic features subsequently. Differentially expressed (DE) genes, DE-lncRNAs and cis/trans target genes of DE-lncRNAs were further compared among the three groups. The KEGG analysis indicated that specific intergroup DEGs were involved in carbon metabolism (S vs. T), metabolic pathways (N vs. T) and focal adhesion pathway (N vs. S), respectively. Whereas, the cis/trans genes of DE-lncRNAs were enriched in cytokine-cytokine receptor interaction, toll-like receptor signaling pathway, p53 signaling pathway and insulin signaling pathway, which play crucial roles in immune system of the host animal. This suggests T. gallinae invasion in pigeon mouth may modulate lncRNAs expression and their target genes. Moreover, co-expression analysis identified crucial lncRNA-mRNA interaction networks. Several DE-lncRNAs including MSTRG.82272.3, MSTRG.114849.42, MSTRG.39405.36, MSTRG.3338.5, and MSTRG.105872.2 targeted methylation and immune-related genes, such as JCHAIN, IL18BP, ANGPT1, TMRT10C, SAMD9L, and SOCS3. This implied that DE-lncRNAs exert critical influence on T. gallinae infections. The quantitative exploration of host transcriptome changes induced by T. gallinae infection broaden both transcriptomic and epigenetic insights into T. gallinae resistance and its pathological mechanism.

In Vivo Efficacy of Clove Essential Oil Ointment for Microsporum gallinae Avian Dermatophytosis-A Randomized Controlled Trial.

Avian favus (dermatophytosis) is a superficial mycosis caused by Microsporum gallinae in poultry. This disease is an important problem in poultry husbandry, but the standard antifungal treatment can leave drug residues in farm products. The aim of this study was to compare the efficacy of a clove essential oil ointment (3%, w/w) with commercially available ketoconazole cream (2%, w/w) for the treatment of M. gallinae infection in chickens. An in vitro time-kill assay showed that clove essential oil ointment reduced the number of viable M. gallinae ATCC 90749 by 99.99% within 1 hr. A randomized controlled trial showed that the therapeutic efficacy of clove essential oil ointment (3%, w/w) was noninferior to ketoconazole cream (2%, w/w) in M. gallinae-infected chickens. The percentage of completely recovered (culture-negative) animals in both treatment groups was 90% in day 35 after initial treatment. This study indicates that clove essential oil is suitable for preparation as an alternative topical treatment for avian dermatophytosis.

PHYSIOLOGICAL AND BIOCHEMICAL RESPONSE OF LAYING HEN’S ORGANISM TO DERMANYSSUS GALLINAE

The paper discusses physiological and biochemical aspects of relations in the "parasite-host" system by the example of market Hy-Line laying hens and Dermanyssus gallinae. The hens of the experimental group were kept in a poultry house with a degree of D. gallinae infection at "+++"; this condition was considered as a stress factor for the birds. The control group had no parasitic agents. Blood was taken from 10 randomly selected birds from the experimental and control groups to determine physiological, biochemical and morphophysiological parameters. The complex of parameters was analyzed for carbohydrate-energy, protein and lipid metabolisms. The nature of metabolic processes in laying hens in dermanyssosis was assessed. The endocrine system supply of the hen’s organism with stress-associated hormones, in particular cortisol and triiodothyronine, was studied. The paper presents the results of molecular consequences of a stress reaction developed in hens in dermanyssosis. Stress in birds was accompanied by excessively activated lipid peroxidation, and a decrease in antioxidant defense. The trend to an increase in the content of Schiff’s bases, the end products of lipid peroxidation in the experimental hens, allows us to note the chronicity of stress reaction, which causes derangement of metabolism in hens in dermanyssosis. The third stage of stress reaction, the stage of exhaustion, was diagnosed in laying hens in dermanyssosis.

Changes in the diversity and composition of gut microbiota in pigeon squabs infected with Trichomonas gallinae

Pigeons, as the only altricial birds in poultry, are the primary Trichomonas gallinae (T. gallinae) host. To study the effects of T. gallinae infection on gut microbiota, we compared the microbiota diversity and composition in gastrointestinal (GI) tracts of pigeons at the age of 14 and 21 day with different degrees of T. gallinae infection. Thirty-six nestling pigeons were divided into three groups: the healthy group, low-grade and high-grade trichomonosis group. Then, the crop, small intestine and rectum contents were obtained for sequencing of the 16S rRNA gene V3–V4 hypervariable region. The results showed that the microbiota diversity was higher in crop than in small intestine and rectum, and the abundance of Lactobacillus genus was dominant in small intestine and rectum of healthy pigeons at 21 days. T. gallinae infection decreased the microbiota richness in crop at 14 days. The abundance of the Firmicutes phylum and Lactobacillus genus in small intestine of birds at 21 days were decreased by infection, however the abundances of Proteobacteria phylum and Enterococcus, Atopobium, Roseburia, Aeriscardovia and Peptostreptococcus genus increased. The above results indicated that crop had the highest microbiota diversity among GI tract of pigeons, and the gut microbiota diversity and composition of pigeon squabs were altered by T. gallinae infection.

Prevalence of Trichomonas gallinae infection in Pigeon of Jessore District, Bangladesh.

Objective:This study was conducted to estimate the prevalence of Trichomonas gallinae infection in pigeon and determination of spatial factors related with T. gallinae infection among smallholder farms at Abhaynagar and Monirampur Upazillas, Jessore District, Bangladesh.Materials and Methods:This cross-sectional study has undertaken from November 24, 2017 to February 28, 2018 on randomly selected 60 pigeons from 12 smallholder farms. Wet smear technique has been used to identify T. gallinae, from swab samples collected from oropharynx and crop of the sampled birds.Results:The overall prevalence was 60% (95% CI: 46.5–72.4) in which 75% (95% CI: 55.1–89.3), 50% (95% CI: 23.0–76.9), and 44.4% (95% CI: 21.5–69.2) were in squab, adult male, and adult female, respectively. The prevalence, in the case of dead pigeons (n = 13), 69.2% showed positive to the protozoan infection in the study. On the basis of spatial distribution, T. gallinae infection in the rural area was 64% (n = 25) followed by urban area 57.1% (n = 35) of the district. The prevalence of T. gallinae was insignificantly higher at Abhaynagar upazilla in contrast to Monirampur upazilla (30%) of Jessore district.Conclusion:This research finding suggests that a significant level of (57.4%) T. gallinae infection is circulating among the pigeon population of Bangladesh. Therefore, proper housing, feeding, and disease management should be ensured by the owner to prevent this problem.

Dermanyssus gallinae eradication approach – application of inert compounds and integral animal health protection

The generally accepted approach to D. gallinae control is based on the control of infestations. The reduction of D. gallinae infection to an acceptable level can temporarily prevent its harmful effects on the health status ofpoultry. However, the reduced number of D. gallinae continues to persist in poultry environment resulting in an intensive increase of infestation rate and consequent transmission of infectious and contagious diseases. Contrary to suppression, the eradication approach completely eliminates D. gallinae thus improving general health status of the flock and providing the control of infectious and contagious diseases associated with this organismand eliminating other adverse effects. Biological efficiency and selection of inert compounds was performed in laboratory conditions. The previous experience with application of SiO2 formulations in practice confirmed thepossibility of successful eradication in 8 cases (combined application of liquid and powdered form). New generation of inert compounds (P 547/17) showed a range of superior properties as compared with SiO2 formulations,especially in view of high and long-lasting residual effects on non-absorbent surfaces. In laboratory conditions, after 7 months, the layer formed by a 20% working emulsion on a metal substrate exhibited efficiency of 92%after 1-hour exposure. In clinical conditions, the presence of mites was not detected even after 6.5 months of the settlement of the flock. Clinical tests of inert oils are still ongoing, but their high potential for the eradication of D.gallinae The eradication of D. gallinae is highly complex procedure, which cannot be performed at all times and in all conditions. The conditions for the eradication of D. gallinae using inert compounds include adequate hygienic preparation of the facilities while still empty, adequate application of selected compounds, and then adequate ambient temperatures which leads to increase of mites activity. The program of D. gallinae control includesprocedures for the preparation, implementation, eradication checks, and prevention of re-infestation

PREVALENCE AND RISK FACTORS OF TRICHOMONAS GALLINAE AND TRICHOMONOSIS IN GOLDEN EAGLE ( AQUILA CHRYSAETOS) NESTLINGS IN WESTERN NORTH AMERICA.

Avian trichomonosis, caused by the protozoan Trichomonas gallinae, affects bird-eating raptors worldwide. Raptors can develop trichomonosis by feeding on infected prey, particularly Rock Pigeons (C olumba livia), which are a reservoir for T. gallinae. Raptors may be particularly vulnerable to T. gallinae infection in degraded habitats, where changes in resources may cause raptors to switch from foraging on native prey to synanthropic avian species such as Rock Pigeons. Golden Eagles ( Aquila chrysaetos) typically forage on mammals; however, habitat across much of their range is experiencing degradation through changes in land use, climate, and human encroachment. In 2015, we examined the prevalence of T. gallinae infection in Golden Eagle nestlings across western North America and conducted an intensive study on factors associated with T. gallinae infection and trichomonosis in southwestern Idaho. We found T. gallinae infection in 13% (12/96) of eagle nestlings across 10 western states and in 41% (13/32) of nestlings in southwestern Idaho. At the Idaho site, the probability of T. gallinae infection increased as the proportion of Rock Pigeons in nestling diet increased. Nestlings with diets that consisted of ≥10% Rock Pigeons had a very high probability of T. gallinae infection. We compared historical (1971-81) and recent (2014-15) diet data and incidence of trichomonosis lesions of nestling eagles in Idaho and found that the proportion of Rock Pigeons in eagle diets was higher in recent versus historical periods, as was the proportion of eagle nestlings with trichomonosis lesions. Our results suggested that localized shifts in eagle diet that result from habitat degradation and loss of historical prey resources have the potential to affect Golden Eagle nestling survival and supported the hypothesis that land use change can alter biologic communities in a way that might have consequences for disease infection and host susceptibility.

Prevalence of Haemoproteus columbae (Apicomplexa: Haemoproteidae) and Trichomonas gallinae (Metamonada: Trichomonadidae) Infections Among Pigeons (Columba livia) in West Azerbaijan Province, Iran.

A cross-sectional survey was performed on domestic pigeons (Columba liviadomestica) to evaluate the prevalence of Haemoproteus columbae and Trichomonas gallinae in West Azerbaijan Province, northwest of Iran between July 2015 and September 2016. Five hundred and sixty oropharyngeal swab smears were examined, 297 (53%) of which were identified to be positive for T. gallinae. Also, the results obtained from blood smears examination indicated that 115 (20.5%) cases were found to be infected with H. columbae. The rates of T. gallinae and H. columbae infection infemale pigeons (58.3% and 21.3%, respectively) were higher compared to those in males. There were 76 (26.1%) and 210 (72.4%) cases of H. columbae and T. gallinae infection in adolescent birds, respectively, which were higher than those in other age groups. We found high prevalence rates of H. columbae and T. gallinae infections in domestic pigeons. Therefore, more attention should be focused on controlling the spread of T. gallinae and H. columbae infection in domestic pigeons.

TetratrichomonasandTrichomonasspp.-Associated Disease in Free-Ranging Common Eiders (Somateria mollissima) from Wellfleet Bay, MA and Description of ITS1 Region Genotypes

During an outbreak of Wellfleet Bay virus (WFBV) in common eiders ( Somateria mollissima) from the Cape Cod region of Massachusetts, several birds were diagnosed with trichomonosis consisting of multiple trichomonad species. Six birds were examined, with trichomonads found in ceca in four birds and associated typhlitis in three of these four birds. PCR and DNA sequencing utilizing trichomonad-specific primers targeting the ITS1 region of the ribosomal DNA (rDNA) revealed the presence of Tetratrichomonas gallinarum in the gastrointestinal tracts of five birds and Trichomonas spp. in the livers of two birds, one of which had a dual Te. gallinarum-Trichomonas gallinae infection. Sequence analysis revealed no variation between Te. gallinarum sequences whereas the ITS1 sequences obtained from the other Trichomonas spp. demonstrated the presence of multiple genotypes. One sequence had 100% identity to a Trichomonas sp. previously isolated from a Cooper's hawk ( Accipiter cooperii) and the other sequence was 100% identical to a previously described Tr. gallinae isolate obtained from a Pacific Coast band-tailed pigeon ( Patagioenas fasciata monilis). These findings suggest Te. gallinarum and other Trichomonas spp. possibly contributed to morbidity and mortality in this species. Furthermore, to the authors' knowledge, this is the first report of trichomonad-associated disease in a free-ranging sea duck.

Molecular investigations of cytochrome c oxidase subunit I (COI) and the internal transcribed spacer (ITS) in the poultry red mite, Dermanyssus gallinae, in northern Europe and implications for its transmission between laying poultry farms

Samples of Dermanyssus gallinae (DeGeer) (Acari: Dermanyssidae) from more than 49 Norwegian and Swedish laying poultry farms, and additional samples collected from Scottish, Finnish, Danish and Dutch layer farms, were compared genetically. Analysis of partial mitochondrial gene cytochrome c oxidase subunit I (COI) sequences of mites from Norway and Sweden revealed 32 haplotypes. Only single haplotypes were found on most farms, which suggests that infections are recycled within farms and that transmission routes are few. Both Norwegian and Swedish isolates were found in the two major haplogroups, but no haplotypes were shared between Norway and Sweden, indicating little or no recent exchange of mites between these countries. There appears to be no link between haplotypes and geographical location as identical haplotypes were found in both the northern and southern Swedish locations, and haplotypes were scattered in locations between these extremes. The current data suggest that wild birds in Sweden are not a reservoir for D. gallinae infection of layer farms as their mites were genetically distinct from D. gallinae of farm layer birds. Transmission of the poultry red mite in Scandinavia is thus likely to depend on synantropic factors such as the exchange of contaminated material or infested birds between farms or facilities.

Genetically different clonal isolates of Trichomonas gallinae, obtained from the same bird, can vary in their drug susceptibility, an in vitro evidence

Trichomonas gallinae is a flagellated protozoon which parasitizes in the upper digestive tract of different birds, especially columbiformes (doves and pigeons) and falconiformes. The parasite is also a common inhabitant of the crop of psittacine birds and is frequently detected in budgerigars. The lesions associated with T. gallinae infection of the upper digestive tract range from mild inflammation of the mucosa to large caseous lesions that block the lumen of the oesophagus. Nitroimidazoles are considered to be the drugs of choice for the treatment of trichomonosis. However, only a few studies report the existence of resistant strains of T. gallinae to these drugs. Thus, in the present investigation cloned cultures of T. gallinae obtained from budgerigars and pigeons were analysed for the first time for their in vitro susceptibilities against four 5´-nitroimidazole derivates, including metronidazole, dimetridazole, ronidazole and ornidazole. Significantly different minimal lethal concentrations (MLCs) were observed for them against all four drugs. The lowest MLCs revealed the Trichomonas isolates obtained from two budgerigars, ranging from 2.0 ± 0.3 to 3.0 ± 0.7 μg/ml for metronidazole and dimetridazole, and from 2.0 ± 0.6 to 6.7 ± 1.7 μg/ml for ornidazole and ronidazole. Contrary to this, the highest MLCs were recorded for one Trichomonas isolate obtained from a pigeon, ranging from 83.3 ± 6.7 (for dimetridazole and ronidazole) to 103.3 ± 3.3 μg/ml (for metronidazole and ornidazole). The data obtained for the resistance testing were further compared with already available genetic data of the small subunit rRNA gene sequences and ITS-1, 5.8S rRNA and ITS-2 sequences, indicating a certain correlation between in vitro results and strain relationships.

Health of an ex situ population of raptors (Falconiformes and Strigiformes) in Mexico: diagnosis of internal parasites

Successful programs for ex situ and in situ conservation and management of raptors require detailed knowledge about their pathogens. The purpose of this study was to identify the internal parasites of some captive raptors in Mexico, as well as to verify their impact in the health status of infected birds. Birds of prey were confiscated and kept in captivity at the Centro de Investigación y Conservación de Vida Silvestre (CIVS) in Los Reyes La Paz, Mexico State. For this, fecal and blood samples from 74 birds of prey (66 Falconiformes and eight Strigiformes) of 15 species, juveniles and adults from both sexes (39 males and 35 female), were examined for the presence of gastrointestinal and blood parasites. Besides, the oropharyngeal cavity was macroscopically examined for the presence of lesions compatible with trichomoniasis. Among our results we found that lesions compatible with Trichomonas gallinae infection were detected only in two Red-tailed hawks (Buteo jamaicensis) (2.7%); nevertheless, infected birds were in good physical condition. Overall, gastrointestinal parasites were found in 10 (13.5%) raptors: nine falconiforms (13.6%) and one strigiform (12.5%), which mainly presented a single type of gastrointestinal parasite (90%). Eimeria spp. was detected in Harris's hawk (Parabuteo unicinctus), Swainson's hawk (Buteo swainsoni), Red-tailed hawk (B. jamaicensis) and Great horned owl (Bubo virginianus); whereas trematodes eggs were found in Peregrine falcon (Falco peregrinus) and Swainson's hawk (B. swainsoni). Furthermore, eggs of Capillaria spp. were found in one Swainson's hawk (B. swainsoni), which was also infected by trematodes. Hemoprotozoarian were detected in five (6.7%) falconiforms: Haemoproteus spp. in American kestrel (F. sparverius) and Leucocytozoon spp. in Red-tailed hawk (B. jamaicencis). Despite this, no clinical signs referable to gastrointestinal or blood parasite infection were observed in any birds. All parasites identified were recorded for the first time in raptors from Mexico. Furthermore, this represents the first report for T. gallinae, trematodes, Haemoproteus spp. and Leucocytozoon spp. in raptors from Latin America. Diagnosis and control of parasitic infections should be a part of the routine in health care evaluations for ex situ raptor populations. Finally, this information is also valuable for in situ conservation actions on these birds.

Epidemiology and conservation implications of Trichomonas gallinae infection in the endangered Mauritian pink pigeon

Despite increasing recognition of the role of exotic pathogens in species decline, comprehensive studies of wildlife disease epidemiology in threatened species are rare. We investigated the epidemiology of the protozoan parasite Trichomonas gallinae, which causes the avian disease trichomonosis, in the five wild subpopulations of the endangered pink pigeon Columba mayeri in Mauritius. An average of 89% of the entire population was screened for T. gallinae infection every 2 months between September 2002 and April 2004. A total of 426 individual pink pigeons (all >3 months of age) was screened, and 359 (84.3%) of these tested positive for T. gallinae at least once. Average prevalence of T. gallinae infection across all subpopulations and sampling periods was 50.3% but ranged from 19.6% to 82.4%. Trichomonas gallinae infection was significantly different among subpopulations and prevalence gradually decreased over the entire screening period. Infection prevalence also increased with host age. Observed pathogenicity of T. gallinae was low; active trichomonosis signs were recorded in ca. 1.9% of birds which tested positive. However, birds which persistently tested positive for T. gallinae (33.5% of birds screened) were at least 10% less likely to survive 2 yrs post-screening than birds which tested negative at least once in three consecutive periods; a finding which should be considered by wildlife disease investigators if no pathogenic effects are apparent from the results of studies based on a single screening episode. We conclude that T. gallinae is an additional population limiting factor for pink pigeons and our study highlights the importance of screening other endangered columbids for this pathogen.

Trichomonas gallinae in budgerigars and columbid birds in Perth, Western Australia.

To estimate the prevalence of infection with Trichomonas gallinae and other parasites of the alimentary tract in psittacine and columbid birds in Perth and to determine in vitro the effectiveness of drugs commonly recommended for treating trichomoniasis. Samples of crop contents were collected from aviary flocks of budgerigars (Melopsittacus undulatus) and other psittacine and columbid birds in both private and commercial collections in Perth. Similar samples from wild Senegal doves (Streptopelia senegalensis) also were collected. Crop contents were examined and cultured for Trichomonas gallinae and in vitro studies were conducted on the susceptibility of isolates to several drugs used commonly. Other parasites also were detected by faecal examination and/or necropsy. T gallinae was recovered from birds in 1 of 13 private collections of budgerigars (2/289 birds in total). Direct wet-mount examination of crop fluid identified 36.4% of samples at four commercial bird dealers which were later determined by culture to contain T gallinae. The prevalence of T gallinae infection range from 0 to 11.4% in budgerigars. The prevalence of T gallinae infection of wild Senegal doves was 46% and from one flock of racing pigeons was 59%. The in vitro minimum lethal concentrations of metronidazole, dimetridazole and ronidazole ranged from 40 to 96, 30 to 80 and 40 to 92 micrograms/mL respectively for six isolates of T gallinae. Other alimentary parasites detected during the survey included Spironucleus sp (syn. Hexamita sp), coccidia, Ascaridia platycerci and Raillietina sp. Thirteen budgerigar flocks belonging to members of avicultural societies in Perth had a low prevalence of trichomoniasis and other parasitic infections. The dose rate currently recommended for ronidazole may not result in complete protozoacidal activity against T gallinae infection.

Pharmacokinetics and anti-trichomonal efficacy of a dimetridazole tablet and water-soluble powder in homing pigeons (Columba livia).

The anti-trichomonal efficacy and pharmacokinetics of dimetridazole were investigated in the homing pigeon (Columba livia). Dimetridazole was formulated for drinking water medication and as a prolonged-release tablet. To suppress a Trichomonas gallinae infection successfully, medicated drinking water containing dimetridazole (400 mg/L) had to be administered for at least 3 days. A two-day treatment with a dimetridazole tablet (20 mg/tablet) in fasted, as well as in fed, pigeons was shown to be ineffective. After intravenous administration of 20 mg dimetridazole, the drug plasma concentration-time profile fitted a one-compartment open model with a mean half-life of 3.9 h. The absolute bioavailability of the tablet in fasted pigeons was 83.8%. The bioavailability of the tablet administered with food was reduced by 20%. Dimetridazole was rapidly metabolised to (1-methyl-5-nitroimidazol-2-yl) methanol.