Prevalence, Genetic Diversity, and Pathogenicity of Avian Haemosporidian Parasite Co-infection in Free-Living Long-Eared Owls (Asio otus).

BackgroundThe long-eared owl (Asio otus) has a Holarctic distribution, including much of North America. This nocturnal species is considered to be extremely secretive, and poorly known in the Great Plains of the United States and Canada, as well as to México, where no previous studies on its diet have been conducted.FindingsWe analyzed 120 pellets collected during January 2007 in roosts in a 2–3 m height mesquite scrub within a grassland area of Reserva Ecológica El Uno, located in the Natural Protected Area Janos. We registered and identified three orders, four families, eight genera and ten species of mammals and two orders and one family of insects. Winter diet is dominated by mammals, especially rodents in both frequency and biomass. Cricetidae and Perognathus flavus were the most frequent family and species, respectively. On the other hand, when analyzing biomass, Sigmodon species were dominant, achieving almost 70% of the consumed biomass. Levin's standardized niche breath based on frequency was calculated as 0.40, while based on biomass was 0.38. Also, two previously unrecorded rodent species were identified as long-eared owl prey.ConclusionAlthough 18 different types of items were identified, the long-eared owl tends to be selective, with a single genera (Sigmodon) comprising almost 70% of its consumed biomass during winter. Perognathus flavus was also important in frequency (21%); however, it barely constitutes 2% of the consumed biomass.

BackgroundHighly pathogenic avian influenza virus (HPAIV) is a highly contagious disease which is a zoonotic pathogen of significant economic and public health concern. The outbreaks caused by HPAIV H5N1 of Asian origin have caused animal and human disease and mortality in several countries of Southeast Asia, such as Bangladesh, Cambodia, China, India, Indonesia, Laos, Myanmar, Thailand and Viet Nam. For the first time since 1961, this HPAIV has also caused extensive mortality in wild birds and has sparked debate of the role wild birds have played in the spread of this virus. Other than confirmed mortality events, little is known of this virus in wild birds. There is no report on the seroprevalence of avian influenza H5 infection in wild migratory birds in Yunnan Province. In this study we examined live wild birds in Yunnan Province for H5 specific antibody to better understand the occurrence of this disease in free living birds.MethodsSera from 440 wild birds were collected from in Kunming and Northern Ailaoshan of Yunnan Province, Southwestern China, and assayed for H5 antibodies using the hemagglutination inhibition (HI) assays.ResultsThe investigation revealed that the seroprevalence of avian influenza H5 was as following: Ciconiiformes 2.6%, Strigiformes 13.04%, Passeriformes 20%, Cuculiformes 21.74%, Gruiformes 0%, Columbiformes 0%, Charadriiformes 0% and Coraciiformes 0%. Statistical analyses showed that there was a significant difference of prevalence between the orders (P < 0.01). Specific avian influenza H5 antibodies were detected in 23 of 440 (5.23%) sera. Mean HI titer 23 positive sera against H5 were 5.4 log2.ConclusionsThe results of the present survey indicated that the proportion of wild birds had previously infected AIV H5 at other times of the year. To our knowledge, this is the first seroprevalence report of avian influenza H5 infection in wild migratory birds in China’ s southwestern Yunnan Province. The results of the present survey have significant public health concerns.

Little is known about the prevalence of encysted Toxoplasma gondii in wild birds. We examined the hearts and breast muscles from 101 raptors for encysted T. gondii. All of the raptors had been submitted for necropsy to the State Veterinary Diagnostic Laboratory, Auburn, Alabama. Tissues were digested in acid-pepsin solution and inoculated into groups of 3-5 laboratory mice. Toxoplasma gondii was isolated from 27 of 101 (26.7%) raptors: 8 of 12 (66.7%) red-shouldered hawks (Buteo lineatus), 13 of 27 (41.1%) red-tailed hawks (Buteo jamaicensis), 1 of 4 (25%) Cooper's hawks (Accipiter cooperi), 1 of 5 (20%) great horned owls (Bubo virginianus), 4 of 15 (26.7%) barred owls (Strix varia), and 1 of 3 (33.3%) kestrels (Falco sparverius). Toxoplasma gondii was not isolated from 3 broad-winged hawks (Buteo platypterus), 3 sharp-shinned hawks (Accipiter striatus), 6 barn owls (Tyto alba), 9 screech owls (Asio otus), a Mississippi kite (Ictinia misisippiensis), 2 golden eagles (Aquila chrysaetos), a bald eagle (Haliaeetus leucocephalus), 4 ospreys (Pandion haliaetus), 4 turkey vultures (Cathartes aura), or 2 black vultures (Coragyps atratus). No significant difference (P > 0.05) in prevalence was detected based on sex using chi-square analysis. Chi-square analysis of the data demonstrated that adult raptors had encysted stages of T. gondii significantly (P < 0.05) more often than did immature raptors.

[Experiment I was carried out to test the hypothesis that the capacity to refrain from responding when reinforcement is withdrawn (behaviour dependent on internal inhibition) is weak in very young birds, develops as a result of age and also as a result of variety of experience during the juvenile stage and later weakens slightly. Two groups of birds were given the task of differentiating between a dish containing food and covered with a white lid and an empty dish covered with a black lid. All were wild birds, but Group I were taken as nestlings, reared by hand and kept indoors. Group II were taken as juveniles or as adults, tested indoors and then released. They were tested at ages ranging from 4½ weeks onwards. The results as they stand are consistent with the hypothesis stated, but some difficulties of interpretation are discussed. In Experiment II an attempt was made to measure changes in level of activity or positive responsiveness in a single brood of hand-reared great tits during a period of time comparable with Experiment I. In two experiments where (1) a previously reinforced and (2) a completely unfamiliar object was introduced into the birds' cages for a limited period of time, the length of time spent by birds pecking and pulling at this object appeared to increase until about 12-15 weeks after fledging, and later decreased again. In the discussion the relation between results from Experiments I and II are considered: it is suggested that changes observed in internal inhibition and positive responsiveness may in fact be changes in different aspects of excitability. This would suggest that excitability increases up to a certain age, and then falls off again., Experiment I was carried out to test the hypothesis that the capacity to refrain from responding when reinforcement is withdrawn (behaviour dependent on internal inhibition) is weak in very young birds, develops as a result of age and also as a result of variety of experience during the juvenile stage and later weakens slightly. Two groups of birds were given the task of differentiating between a dish containing food and covered with a white lid and an empty dish covered with a black lid. All were wild birds, but Group I were taken as nestlings, reared by hand and kept indoors. Group II were taken as juveniles or as adults, tested indoors and then released. They were tested at ages ranging from 4½ weeks onwards. The results as they stand are consistent with the hypothesis stated, but some difficulties of interpretation are discussed. In Experiment II an attempt was made to measure changes in level of activity or positive responsiveness in a single brood of hand-reared great tits during a period of time comparable with Experiment I. In two experiments where (1) a previously reinforced and (2) a completely unfamiliar object was introduced into the birds' cages for a limited period of time, the length of time spent by birds pecking and pulling at this object appeared to increase until about 12-15 weeks after fledging, and later decreased again. In the discussion the relation between results from Experiments I and II are considered: it is suggested that changes observed in internal inhibition and positive responsiveness may in fact be changes in different aspects of excitability. This would suggest that excitability increases up to a certain age, and then falls off again.]

Simple SummaryWildlife may be zoonotic carriers of pathogens. The aim of this paper was to investigate the presence of Campylobacter (C.) jejuni and C. coli, which are responsible for enteric syndromes and sometimes extraintestinal diseases in humans, in wild birds housed at a wildlife rescue centre. Sensitivity to antibiotics was also investigated in the detected strains. Two hundred and nine birds belonging to 33 different species were considered in the study. Campylobacter was found in 52 birds (24.88%), mainly in omnivorous species. In terms of housing conditions, the infection rate was higher in birds housed in indoor (57.14%) than in outdoor aviaries (31.74%). Interestingly, Campylobacter was not detected in some species whose mean temperature body was below 40 °C or higher than 42.2 °C. All detected strains were C. jejuni except for three C. coli that were identified in Long-eared Owls. The most commonly found antibiotic resistance was against drugs such as trimethoprim/sulfamethoxazole, ciprofloxacin and enrofloxacin. Multi-drug resistance against two or more antibiotics was also detected. The findings of the study highlight the relevance of increasing biosecurity measures at the wildlife rescue centres to reduce health risks to staff involved in wildlife management.Climate change, excessive exploitation of agricultural land which reduces natural habitats, wildlife shooting, and the use of pesticides all cause difficulties for wildlife, with considerable numbers of animals being brought to wildlife rescue centres. Although the efforts of staff involved in wildlife management at these centres usually focus on therapeutic treatments to reintroduce them into the wild, the monitoring of pathogens that may be transmitted to humans is of relevance. Campylobacter (C.) jejuni and C. coli are frequently carried by animals without inducing clinical signs and are responsible for enteric disorders and more rarely extra-intestinal disease in humans. Farm species and poultry, in particular, are the main reservoirs of C. jejuni and C. coli, but wild animals may also be carriers. The aim of this paper was to investigate the presence of C. jejuni and C. coli in wild birds housed at a wildlife rescue centre and to evaluate the sensitivity of the detected strains to antibiotics. Campylobacter was found in 52 out of 209 (24.88%) birds from 33 different species. C. jejuni was more prevalent, while C. coli was only detected in three Long-eared Owls (Asio otus). The incidence of the infection was particularly high (72.22%) among omnivorous species. Infection rates were higher in birds housed indoors (57.14%) than outdoors (31.74%). Moreover, Campylobacter was not detected in species whose mean temperature body is below 40 °C or higher than 42.2 °C. The most common antibiotic resistance in the tested strains was against trimethoprim/sulfamethoxazole, ciprofloxacin and enrofloxacin. In addition, multi-drug resistance was also found. The results highlight the need to increase biosecurity measures at rescue centres so as to reduce health-related risks to workers involved in wildlife management.

In the present study, lead, zinc and copper concentrations in the feathers of Common kestrel (Falco tinnunculus), Eurasian magpie (Pica pica), Common buzzard (Buteo buteo), Crested lark (Galerida cristata), Eurasian hoopoe (Upupa epops), Little owl (Athene noctua), Long-eared owl (Asio otus), Eurasian eagle-owl (Bubo bubo) and Long-legged buzzard (Buteo rufinus) from Sabzevar and Neghab, Khorasan Razavi of Iran were measured. Almost all of the specimens were obtained from birds that had collided with vehicles or were unable to fly. There were no significant differences in metal concentrations between adult and juvenile, diurnal and nocturnal raptors and species with different diets. Elemental concentrations were lower than toxicity threshold values, so exposure to these elements does not appear to pose a health risk to the studied species. It should be noted that this study was the first study of metals in Galerida cristata, Asio otus and Buteo rufinus.

Niche theory predicts that closely related and ecologically similar species with overlapping distribution ranges can coexist through resource partitioning that limits interspecific competition. However, studies examining the mechanisms promoting coexistence of top predators at a large geographical scale are still scant. Here, we describe the foraging ecology of 3 sympatric owl species (Northern long-eared owl [Asio otus], Tawny owl [Strix aluco], Eurasian eagle owl [Bubo bubo]) in the Mediterranean Basin. We review 160 studies reporting diet information (212,236 vertebrate preys) and investigate among-species differences in diet metrics (diversity, evenness, prey size, and proportion of mammals) and their variation along geographical and environmental gradients. Moreover, we test whether diet metrics differ in presence or absence of the other predators. All the 3 species mainly rely on small mammals, but they significantly differ in diet metrics. The smallest predator (i.e., long-eared owl) shows a higher level of specialism on small mammals (highest proportion but lowest diversity of mammals in the diet) compared to the larger ones. In addition, mean prey size significantly increases with predator body size (long-eared owl < tawny owl < eagle owl). Finally, interspecific competition results in an increase of diet diversity and evenness in the long-eared owl, and species' diet also varies in response to environmental factors. The 3 species thus segregate along several dietary niche axes over a large spatial scale and according to both morphological characteristics (i.e., body size) and environmental variables. Such dietary niche segregation may adaptively buffer interspecific competition costs, ultimately allowing coexistence.

There is growing interest in avian influenza (AI) epidemiology to predict disease risk in wild and domestic birds, and prevent transmission to humans. However, understanding the epidemic dynamics of highly pathogenic (HPAI) viruses remains challenging because they have rarely been detected in wild birds. We used modeling to integrate available scientific information from laboratory and field studies, evaluate AI dynamics in individual hosts and waterfowl populations, and identify key areas for future research. We developed a Susceptible-Exposed-Infectious-Recovered (SEIR) model and used published laboratory challenge studies to estimate epidemiological parameters (rate of infection, latency period, recovery and mortality rates), considering the importance of age classes, and virus pathogenicity. Infectious contact leads to infection and virus shedding within 1–2 days, followed by relatively slower period for recovery or mortality. We found a shorter infectious period for HPAI than low pathogenic (LP) AI, which may explain that HPAI has been much harder to detect than LPAI during surveillance programs. Our model predicted a rapid LPAI epidemic curve, with a median duration of infection of 50–60 days and no fatalities. In contrast, HPAI dynamics had lower prevalence and higher mortality, especially in young birds. Based on field data from LPAI studies, our model suggests to increase surveillance for HPAI in post-breeding areas, because the presence of immunologically naïve young birds is predicted to cause higher HPAI prevalence and bird losses during this season. Our results indicate a better understanding of the transmission, infection, and immunity-related processes is required to refine predictions of AI risk and spread, improve surveillance for HPAI in wild birds, and develop disease control strategies to reduce potential transmission to domestic birds and/or humans.

The results of the complex parasitological studies conducted in the wild birds of hunting interest as well as domestic birds demonstrates that the phenomenon of the poliparasitism is a static one, although the poliparasitic quantitative and qualitative structure is continuously changing. This is due to instantaneous contact of the wild birds with the domestic ones, irregular deparasiting of domestic animals and their crates, reduced areas for animals breading and maintenance that ensures the permanent contact with the wild birds as the infestation source. The findings of the study on the diversity of the ectoparasitic fauna in wild birds from various anthropic biotopes of Moldova revealed that the wild and domestic birds are infested with multiple parasites and that the most identified parasitoses are common for major birds of hunting interest as well as for the domestic birds.

Raptor population growth is dynamic and trends vary across species and by location in the United States. For those species that are declining, it is important to identify potential causes including chemical contaminants. Sampling wild raptors is problematic due to their small population sizes and role as a top predator. Therefore, we obtained liver samples (n = 56) from carcasses of several raptor species, including common species like red-tailed hawks, red-shouldered hawks, barred owls, great horned owls, and osprey that arrived dead or were euthanized from a non-profit rehabilitation center in Charlotte, North Carolina. Raptors were found or collected in South Carolina, North Carolina, and Virginia, but most samples were located near the metropolitan region of Charlotte, NC. We analyzed livers for total mercury residue (mg/kg, dry weight) and five anti-coagulant rodenticides (μg/kg wet weight). Mercury was analyzed using a direct mercury analyzer approach and rodenticides were quantified by LC-MS. Mercury residues were high in piscivorous birds (15.09mg/kg for osprey and 6.93mg/kg for great blue herons, dry weight) and relatively high in red-shouldered hawks and one eastern screech owl tested. Six of our samples exceeded a health threshold of 1mg/kg (wet weight) including three osprey and one each of great blue heron, red-shouldered hawk, and eastern screech owl. Brodifacoum was the only rodenticide consistently detected in our samples. Brodifacoum detections exceeded 75% in barred owls, great horned owls, and red-shouldered hawks. Sixty-nine percent of owl samples were within (or exceeded) a threshold of brodifacoum residue associated with a 10-20% risk of acute toxicity. Correlations between residues and human population density were not significant for either mercury or brodifacoum. Our data suggest that mercury residues for most raptors were not of significant concern with the exception of osprey and possibly red-shouldered hawks. Rodenticide exposures associated with a risk of acute toxicity appear to be common and warrant further investigation.

Transovarial antibody transfer in owls has not been demonstrated for West Nile virus (WNV). We sampled chicks from captive adult WNV-antibody-positive Eastern Screech-Owls (Megascops asio) to evaluate the prevalence of transovarial maternal antibody transfer, as well as titers and duration of maternal antibodies. Twenty-four owlets aged 1 to 27 days old circulated detectable antibodies with neutralizing antibody titers ranging from 20 to 1600 (median 1:40). Demonstrating that WNV antibodies are passively transferred transovarially is important for accurate interpretation of serologic data from young birds.

BackgroundIndividuals living in malaria endemic areas generally harbour multiple parasite strains. Multiplicity of infection (MOI) can be an indicator of immune status. However, whether this is good or bad for the development of immunity to malaria, is still a matter of debate. This study aimed to examine the MOI in asymptomatic children between two and ten years of age and to relate it to erythrocyte variants, clinical attacks, transmission levels and other parasitological indexes.MethodsStudy took place in Niakhar area in Senegal, where malaria is mesoendemic and seasonal. Three hundred and seventy two asymptomatic children were included. Sickle-cell trait, G6PD deficiency (A- and Santamaria) and α+-thalassaemia (-α3.7 type) were determined using PCR. Multiplicity of Plasmodium falciparum infection, i.e. number of concurrent clones, was defined by PCR-based genotyping of the merozoite surface protein-2 (msp2), before and at the end of the malaria transmission season. The χ2-test, ANOVA, multivariate linear regression and logistic regression statistical tests were used for data analysis.ResultsMOI was significantly higher at the end of transmission season. The majority of PCR positive subjects had multiple infections at both time points (64% before and 87% after the transmission season). MOI did not increase in α-thalassaemic and G6PD mutated children. The ABO system and HbAS did not affect MOI at any time points. No association between MOI and clinical attack was observed. MOI did not vary over age at any time points. There was a significant correlation between MOI and parasite density, as the higher parasite counts increases the probability of having multiple infections.ConclusionTaken together our data revealed that α-thalassaemia may have a role in protection against certain parasite strains. The protection against the increase in MOI after the transmission season conferred by G6PD deficiency is probably due to clearance of the malaria parasite at early stages of infection. The ABO system and HbAS are involved in the severity of the disease but do not affect asymptomatic infections. MOI was not age-dependent, in the range of two to ten years, but was correlated with parasite density. However some of these observations need to be confirmed including larger sample size with broader age range and using other msp2 genotyping method.

Reliability of steatocrit as an indicator of intestinal health in young birds – Relationships with morphology and growth rate of canary Serinus canaria nestlings

Co-infection with intestinal parasites and tuberculosis infection is one of the leading causes of morbidity and mortality especially in resource poor countries in sub-Saharan Africa. A cross-sectional study in seven LGAs of Benue State was conducted to determine the prevalence of polyparasitism in tuberculosis patients and apparently healthy individuals. The TB patients were recruited from individuals already participating in the Directly Observed Short-course Treatment (DOTS) programme. These patients had varying degrees of tuberculosis severity and were categorized into scanty infection, light infection (1+), moderate infection (2+) and heavy infection (3+). Stool samples were examined using formal-ether concentration technique. A total of 661 tuberculosis patients were examined for intestinal parasites. 254 (38.4%) had at least one or more intestinal parasites. 153 (23.1%) of them harboured multiple parasites. However, of the 826 apparently healthy individuals, 333 (40.3%) were positive for at least one intestinal parasite. Out of these 333 positive individuals, 191 (23.1%) had multiple infections. Tarka Local Government Area had the highest prevalence (47%) of intestinal parasites which was significantly higher than Apa, the Local Government Area with the least prevalence of 17.7% parasitic infection, and this had no significant difference from the prevalence of multiple parasitism in the remaining six Local Government Areas sampled. On the whole; 1487 individuals were investigated, 557 (36.5%) had intestinal parasites and 364 (24.5%) had multiple parasitism. Eight different type of co-infections were encountered with the most frequent being hookworm and E. histolytica which was significantly higher than other types ( p < 0.05) and was consistently higher in male tuberculosis patients. The occurrence of these co infections increased significantly ( p < 0.05) with TB status of moderate (2+) to heavy infections (3+). The high prevalence of multiple intestinal parasites in tuberculosis patients poses a serious challenge to the current tuberculosis management strategy. Keywords: polyparasitism, tuberculosis, Benue State, Nigeria

Seasonal variation of mercury contamination in Arctic seabirds: A pan-Arctic assessment