Prevalence Of Blood Parasites Research Articles

Socio-Demographic Characteristics and Blood Parasites Among Blood Donors in Two Communities in Delta State, Nigeria

A six months' study was conducted to determine the occurrence of blood parasites in blood donors in Eku and Abraka, Delta State. Random sampling was adopted for blood samples collection alongside socio-demographic characteristics. Laboratory analysis using thick and thin films were carried out on samples. The result showed that 59(29.5%) were positive for blood parasites; 46(23.0%) for Plasmodium, 5(5.0%) for Trypanosoma, and 8(4.0%) for microfilaria. Parasite prevalence was highest in the age-group 45-49 years. Female showed relatively higher prevalence (30.6%) compared to male (29.3%). There was no significant difference in blood parasites prevalence based on gender of the subjects. Blood group B had the dominant prevalence (51.7%). With respect to occupation, self-employed donors had higher prevalence (38.9%). In addition, the rural-urban prevalence was skewed towards rural blood donors (39.7%) with no statistical difference, in respect to residence. PCV of donors showed no clear patterns and there was no association between PCV and prevalence of blood parasites (p>0.05). The results therefore indicate that there is relatively high prevalence of blood parasites among the blood donors which call for the attention of the authority concerned.

Blood and urinary parasites and associated risk factors in a rural community in Abia State, Nigeria

The environment, climate, social behaviour, and economic factors make developing countries vulnerable to parasitic infections. A cross-sectional study was conducted (Dec 2017-May 2018) to determine the prevalence of blood and urine parasites in Obizi, Amakama-Olokoro, a rural community in Umuahia South LGA, Abia State. Blood and urine samples were collected from 284 respondents. Sample analyses were done using Rapid Diagnostic Test (RDT) kits and microscopy for blood and centrifugal sedimentation method for urine. Socio-demographic data and risk factors were collected with structured questionnaires. Statistical analysis was done using the Pearson’s Chi-square, with the PAST Statistical package. The results showed an overall blood parasitic prevalence of 32.4%. Plasmodium falciparum recorded the highest prevalence of 28.17% by RDT and 30.6% by microscopy. Trypanosoma brucei gambiense occurred as a mixed infection (1.8%). Schistosoma haematobium had a prevalence of 3.9%. Socio-demographic data showed there were more females (67.3%); more persons in the age group 61-70 years (31.0%) and more farmers (38.0%) in the studied population. More females were infected with Plasmodium falciparum (34.6%) while more males were infected with Schistosoma haematobium (8.6%) P. falciparum occurred in all the age groups. S. haematobium occurred only in three age groups with the highest prevalence found in the age group (11-20) years (26.9%). Malaria infection was higher in those who did not use ITNs (37.1%). Some reasons given for the non-usage of ITNs were high cost/non-availability and discomfort. Farming activities and swimming have been recognized as risk factors to the acquisition of Trypanosoma brucei gambiense and Schistosoma haematobium, respectively. Plasmodium falciparum, Trypanosoma brucei gambiense and Schistosoma haematobium still pose a serious health threat to the community. Eliminating vector breeding sites, the use of ITNs and changes in social behaviours will help reduce blood and urinary parasites and ensure a healthier and economically viable community.

ASSESSMENT OF VARIATION IN THE DETECTION AND PREVALENCE OF BLOOD PARASITES AMONG SYMPATRICALLY BREEDING GEESE IN WESTERN ALASKA, USA.

Haemosporidian parasites may impact avian health and are subject to shifts in distribution and abundance with changing ecologic conditions. Therefore, understanding variation in parasite prevalence is important for evaluating biologically meaningful changes in infection patterns and associated population level impacts. Previous research in western Alaska, US, indicated a possible increase in Leucocytozoon spp. infection between Emperor Geese (Anser canagicus) sampled in 1996 (<1%, n=134) and during 2011-12 (19.9%, 95% confidence interval [CI]: 3.0-36.8%, n=77); however, different detection methods were used for these estimates. Prior research in this same region identified a lack of Leucocytozoon spp. parasites (0%, n=117) in sympatrically breeding Cackling Geese (Branta hutchinsii minima) in 2011. We molecularly screened blood samples collected from sympatrically breeding Emperor and Cackling Geese in western Alaska during additional breeding seasons to better assess temporal and species-specific variation in the prevalence of blood parasites. We found similar prevalence estimates for Leucocytozoon spp. parasites in Emperor Goose blood samples collected in 1998 and 2014, suggesting consistent infection of Emperor Geese with blood parasites at these time points. Using samples from sympatric geese sampled during 2014, we found evidence for a higher incidence of parasites among Emperor Geese (20.3%, 95% CI: 11.8-32.7%) compared to Cackling Geese (3.6%, 95% CI: 1.1-11.0%), reinforcing the previous finding of species-specific differences in infection. Furthermore, we detected Leucocytozoon, Haemoproteus, and Plasmodium spp. blood parasites in unflighted goslings of both species, supporting the possible transmission of these parasites at western Alaska breeding grounds. Our results help to clarify that prevalence of Leucocytozoon spp. parasites have probably remained consistent among Emperor Geese breeding in western Alaska since the late 1990s and that this species may disproportionally harbor Leucocytozoon spp. compared to sympatrically breeding Cackling Geese.

An alternative combination therapy with metronidazole and doxycycline for babesiosis and theileriosis in stray dogs

In Egypt, scare data explored blood protozoan parasites of stray dogs. Therefore, blood sample from 50 dogs were collected and microscopically examined for blood protozoan parasites by Giemsa-stained thin smear technique. Positive blood parasites cases (Babesiosis and Theileriosis) were blind randomly allocated into two groups to receive a combination of drugs. Group 1: Metronidazole (15mg/kg PO q 12h) with Doxycycline (5mg/kg PO q 12h) Group 2: Quinine (30mg/kg PO q 12H) with Clindamycin (25mg/kg PO q 12h) .The treatment period was seven days, but the first dose administration was given a double for each group. The hematological parameter (RBC; WBC; HCT; MCV; MCH; MCHC and platelets); liver enzyme and kidney function test of each sample were also assessed to follow up the effects of therapies. An overall prevalence of protozoan blood parasites was (33/50) 66%, the revealed species was Babesia spp. (25/33) 75.7% and Theileria spp. (8/33) 24.3%. Babesia gibsoni were the predominant Babesia spp. Physical examination revealed that all measured medical parameters of infected dogs were statistically significant compared to uninfected dogs except body weight and oral CRT (Capillary refill time) was statistically insignificant. The cured rate for group (1) was 56.2% and group (2) was 37.5% with statistically insignificant difference (x2=1.129, p=0.288). Still, the ROC curve values were higher among group (1) than group (2). Its values were (0.594 and 0.406, respectively). So, the combination of Metronidazole with Doxycycline is more suitable due to the area under curve nearest 0.6 while the value of area under curve for the combination of clindamycin with quinine in group (2) less than 0.5. Metronidazole combination therapy with doxycycline is more effective in improving blood parameters such as decreased liver enzymes, increased blood platelets and cure rate than combination therapy of quinine with clindamycin.

Babesia spp. and Anaplasma phagocytophilum in free-ranging wild ungulates in central Austria

Free-ranging wild ungulates are widespread in Austria, and act as hosts (i.e. feeding hosts) for ticks, including Ixodes ricinus, and as reservoir hosts for pathogens transmitted by I. ricinus. Due to climate change, the abundance of I. ricinus might be increasing, which could potentially lead to higher prevalences of tick-borne pathogens, such as Babesia spp. and Anaplasma phagocytophilum, some known for their zoonotic potential. Human babesiosis is classified as an emerging zoonosis, but sufficient data of these parasites in central Austria is lacking. In order to assess the abundance of vector-borne pathogens, blood of roe deer (Capreolus capreolus; n = 137), red deer (Cervus elaphus; n = 37), mouflons (Ovis gmelini; n = 2) and chamois (Rupicapra rupicapra; n = 1), was collected and tested for pathogen DNA in two different sampling sites in central Austria. DNA of tick-borne pathogens was detected in 15.5 % (n = 27) of these animals. Babesia capreoli (n = 22 in roe deer; n = 1 in mouflon), Babesia divergens (n = 1, in red deer), and Anaplasma phagocytophilum (n = 4, in roe deer) were detected. DNA sequencing of the 18S rRNA gene of two C. capreolus samples from Upper Austria featured another new genotype of Babesia, which differs in one nucleotide position to B. divergens and B. capreoli, and is intermediate between the main genotypes of B. capreoli and B. divergens within the partial gene sequence analyzed. This study thus confirms that B. capreoli, B. divergens, and A. phagocytophilum are present in free-ranging ungulates in central Austria. Further testing over a longer period is recommended in order to assess the impact of climate change on the prevalence of blood parasites in central Austria.

Sex and nest type influence avian blood parasite prevalence in a high-elevation bird community

BackgroundThe prevalence of avian haemosporidian parasites and the factors influencing infection in the Colorado Rocky Mountains are largely unknown. With climate change expected to promote the expansion of vector and avian blood parasite distributions, baseline knowledge and continued monitoring of the prevalence and diversity of these parasites is needed.MethodsUsing an occupancy modeling framework, we conducted a survey of haemosporidian parasite species infecting an avian community in the Colorado Rocky Mountains in order to estimate the prevalence and diversity of blood parasites and to investigate species-level and individual-level characteristics that may influence infection.ResultsWe estimated the prevalence and diversity of avian Haemosporidia across 24 bird species, detecting 39 parasite haplotypes. We found that open-cup nesters have higher Haemoproteus prevalence than cavity or ground nesters. Additionally, we found that male Ruby-crowned Kinglets, White-crowned Sparrows, and Wilson’s Warblers have higher Haemoproteus prevalence compared to other host species. Plasmodium prevalence was relatively low (5%), consistent with the idea that competent vectors may be rare at high altitudes.ConclusionsOur study presents baseline knowledge of haemosporidian parasite presence, prevalence, and diversity among avian species in the Colorado Rocky Mountains and adds to our knowledge of host–parasite relationships of blood parasites and their avian hosts.Graphical

Prevalence of canine vector-borne blood parasites in the plain regions of Cambodia

Prevalence of canine vector-borne blood parasites in the plain regions of Cambodia

The effect of habitat quality on the blood parasite assemblage in understorey avian insectivores in the Eastern Himalaya, India

The anthropogenic alteration of natural habitats can modify interactions between various biotic and abiotic factors. The prevalence of avian blood parasites in free‐living host species in the tropics has shown contrasting patterns in altered landscapes. Here, we investigate these potential associations between understorey insectivorous bird species of the Eastern Himalayas and avian haemosporidians in primary and selectively logged forests. We describe patterns related to host–parasite associations, host life‐history traits and host specificity in primary and logged forests. Using parasite‐specific cytochrome‐b gene markers, we screened 545 individual birds from nine families, 33 genera and 57 species. Of these, 34.67% were infected with Leucocytozoon spp., 13.94% with Haemoproteus spp., 3.30% with Plasmodium spp. and 8.44% with co‐infections. We found that parasite prevalence did not change with logging; however, host specificity and life‐history traits did have associations with infection prevalence. We report a vertical stratification in genera‐specific infections driven by vector groups – upper canopy and midstorey foragers had high Leucocytozoon and Haemoproteus prevalence, respectively. In addition, species foraging in mixed‐species flocks showed increased infection risk with Leucocytozoon, whereas solitary foragers had a high prevalence of Plasmodium. This study also highlights that avian parasite lineages are genetically more distinct in primary forest than in logged forest plots. Although our study demonstrates no influence of selective logging on parasite prevalence, it does reflect a positive influence of host abundance and logged habitats on parasite diversity. Our work reveals valuable patterns in terms of phylospecificity and genetic variation in parasite assemblages. Further research with a focus on parasite intensity and vector abundance will help us to understand anthropogenic impacts on parasite transmission dynamics in Eastern Himalayan birds.

Prevalence and genetic diversity of avian haemosporidian parasites in wild bird species of the order Columbiformes

Diseases can play a role in species decline. Among them, haemosporidian parasites, vector-transmitted protozoan parasites, are known to constitute a risk for different avian species. However, the magnitude of haemosporidian infection in wild columbiform birds, including strongly decreasing European turtle doves, is largely unknown. We examined the prevalence and diversity of haemosporidian parasites Plasmodium, Leucocytozoon and subgenera Haemoproteus and Parahaemoproteus in six species of the order Columbiformes during breeding season and migration by applying nested PCR, one-step multiplex PCR assay and microscopy. We detected infections in 109 of the 259 screened individuals (42%), including 15 distinct haemosporidian mitochondrial cytochrome b lineages, representing five H. (Haemoproteus), two H. (Parahaemoproteus), five Leucocytozoon and three Plasmodium lineages. Five of these lineages have never been described before. We discriminated between single and mixed infections and determined host species-specific prevalence for each parasite genus. Observed differences among sampled host species are discussed with reference to behavioural characteristics, including nesting and migration strategy. Our results support previous suggestions that migratory birds have a higher prevalence and diversity of blood parasites than resident or short-distance migratory species. A phylogenetic reconstruction provided evidence for H. (Haemoproteus) as well as H. (Parahaemoproteus) infections in columbiform birds. Based on microscopic examination, we quantified parasitemia, indicating the probability of negative effects on the host. This study provides a large-scale baseline description of haemosporidian infections of wild birds belonging to the order Columbiformes sampled in the northern hemisphere. The results enable the monitoring of future changes in parasite transmission areas, distribution and diversity associated with global change, posing a potential risk for declining avian species as the European turtle dove.

Prevalence of Haemosporidian Parasite Infections in Raptors of Iran

Birds are infected by several genera of blood parasites in the phylum Apicomplexa, Order Haemosporidia: Haemoproteus, Plasmodium, and Leucocytozoon. This broadly distributed and diverse group of parasites greatly influences many aspects of the hosts' lifecycle and can cause diseases and even mortality in birds under natural and captive conditions. We determined the prevalence of haemosporidian blood parasites in raptors in Iran by examining blood samples from 62 raptors (13 species from three families: Accipitridae, Falconidae and Strigidae). We documented the first known report in Iran of haemosporidian infection for several raptor species, including eight novel host records for Haemoproteus and two novel host records for Leucocytozoon. Raptors were infected by Haemoproteus spp. (24% of 62 individuals), Leucocytozoon spp. (3% of individuals), and microfilaria (58% of individuals). Such new information from less-studied countries such as Iran can potentially be used to address conservation and management questions in epidemiological studies of wildlife diseases, veterinary medical treatment of captive birds, and in the investigation of host–parasite relationships.

Mortality cost of sex-specific parasitism in wild bird populations

Sex-specific mortality is frequent in animals although the causes of different male versus female mortalities remain poorly understood. Parasitism is ubiquitous in nature with widespread detrimental effects to hosts, making parasitism a likely cause of sex-specific mortalities. Using sex-specific blood and gastrointestinal parasite prevalence from 96 and 54 avian host species, respectively, we test the implications of parasites for annual mortality in wild bird populations using phylogenetic comparative methods. First, we show that parasite prevalence is not different between adult males and females, although Nematodes showed a statistically significant but small male-biased parasite prevalence. Second, we found no correlation between sex-biased host mortalities and sex-biased parasite prevalence. These results were consistent in both blood and gastrointestinal parasites. Taken together, our results show little evidence for sex-dependent parasite prevalence in adults in wild bird populations, and suggest that parasite prevalence is an unlikely predictor of sex difference in adult mortalities, not withstanding sampling limitations. We propose that to understand causes of sex-biased mortalities, more complex analyses are needed that incorporate various ecological and life history components of animals life that may include sex differences in exposure to predators, immune capacity and cost of reproduction.

Blood Parasites in Domestic Birds in Central Iran.

Parasites may affect the dynamics of bird populations. Plasmodium, Leucocytozoon and Haemoproteus are well-known avian haematozoa that can trigger decreased productivity and high mortality in domesticated birds. In this study, we evaluated the prevalence of avian blood parasites (Plasmodium, Leucocytozoon and Haemoproteus) against 335 birds of 8 species in the Yazd province in central Iran. To detect blood parasites, Giemsa-stained blood smears were prepared. Of the birds, 11.64% (39/335) were infected with at least one parasite genus, particularly Haemoproteus (32.6%; 23/335). The total prevalence values for Plasmodium, Haemoproteus and Leucocytozoon were 1.7, 6.8 and 2.9%, respectively. Plasmodium had lower prevalence rates of 1.7% (6/335). Among birds, pigeons, hens and ducks have the highest prevalence of Haemoproteus, Leucocytozoon and Plasmodium parasites at 1.7%, 6.8% and 2.9%, respectively. Results from this research extend our knowledge on the incidence of avian blood parasites in domesticated birds living in central Iran. The overall low incidence of avian blood parasites in birds was found in the Yazd province, Iran.

Haemosporidian parasites prevalence associated with physical conditioning of avian species from the Brazilian Cerrado

Blood parasites can infect myriad avian species and thereby affect the fitness and survival of their hosts. There is wide interspecific variation in parasite prevalence related to biological, ecological, and evolutionary host factors. This study aimed to determine the blood parasite prevalence in avian species from the Brazilian Cerrado and to investigate the associations among biomass, body condition, and blood parasitism. A total of 1,098 blood smears from 549 individuals (56 species) collected in four forest fragments were analyzed. Of these, 109 (19.85%) individuals from 33 species were infected: 13 (2.36%) were positive for Haemoproteus and 103 (18.76%) for Plasmodium. There was co-infection between both genera of parasites in 7 individuals. Among bird species, prevalence ranged from zero to 100%. There were significant positive correlations between prevalence and biomass and the body condition index. Hemosporid vectors track their hosts by carbon dioxide detection. Since large organisms emit more carbon dioxide, our results suggest that larger birds may be more susceptible to hemosporid vectors. Additionally, species with higher body condition indices can be more tolerant to parasites, possibly because they have more energy reserves. This study showed that species with higher biomass and body condition indices were associated with higher blood parasite prevalence, a finding that suggests these factors are efficient predictors to explain the interspecific variations. This information could be important for the understanding parasite-host relationships and useful for bird conservation programs.

Blood parasites (Babesia, Hepatozoon and Trypanosoma) of rodents, Lithuania: part I. Molecular and traditional microscopy approach.

Wild rodents, as natural reservoir hosts carrying various species of pathogens, play an important role in the evolution and emergence of zoonotic diseases. In this study, protist parasites, namely Babesia sp., Trypanosoma sp. and Hepatozoon sp. were studied in rodent populations in Lithuania. Two hundred forty rodent specimens of seven species were analysed by a combined approach using polymerase chain reaction (PCR)-based techniques and traditional microscopic examination. The total prevalence of blood parasites reached 35% in rodent communities. The prevalence of Hepatozoon sp. reached the highest value (32%), followed by Trypanosoma sp. (5%) and Babesia sp. (3%). Myodes glareolus and Microtus agrestis were the most heavily infected rodent species. Comparison of microscopy and PCR-based methods showed that the two approaches might give different results and thus can lead to an underestimation of the actual prevalence and abundance of parasites. In our study, PCR-based assays were more sensitive and robust than traditional microscopy. However, precise molecular results for the estimation of the prevalence of Babesia sp. and Hepatozoon sp. were achieved only by using several sets of primers. To avoid inaccurate results, the improvement and detailed description of molecular and microscopy protocols are required.

Detection Of Blood Parasites In Cattle In Kutalimbaru Subdistrict, Deli Serdang Regency, North Sumatera

The aim of this research was to identify and to find out the prevalence of blood parasites in cattle in Kutalimbaru Subdistrict, Deli Serdang Regency. This research was conducted in Kutalimbaru Subdistrict, Deli Serdang Regency from December 2018 to February 2019. Normal/healthy cattle of different breeds were randomly selected from five locations, namely Sei Mencirim village, Sawit Rejo village, Silebo-lebo village, Sampe Cita village and Pasar X village. A total of 150 blood samples were collected for blood smears. Diagnostic techniques were tested using Giemsa's staining technique. The blood parasites were then identified and their prevalence was determined. The results showed that one species of blood parasite was successfully identified, all belonging to the blood parasite, namely, Theileria sp. with a prevalence of 33%. In addition, there were no species of blood parasite from the Anaplasma, Trypanosoma, and Babesia. This study suggests that theileriosis is spreading to even the other region in North Sumatera. To reduce the infection, follow up surveys of the blood parasites of the livestock, assess their distribution and infection rates of possible vectors are recommended and plans control measures against should be focused on reducing transmission to highly susceptible animal species.

Prevalence of Haemosporidian Parasite Infections in Raptors of Iran

Birds are infected by several genera of blood parasites in the phylum Apicomplexa, Order Haemosporidia: Haemoproteus, Plasmodium, and Leucocytozoon. This broadly distributed and diverse group of parasites greatly influences many aspects of the hosts' lifecycle and can cause diseases and even mortality in birds under natural and captive conditions. We determined the prevalence of haemosporidian blood parasites in raptors in Iran by examining blood samples from 62 raptors (13 species from three families: Accipitridae, Falconidae and Strigidae). We documented the first known report in Iran of haemosporidian infection for several raptor species, including eight novel host records for Haemoproteus and two novel host records for Leucocytozoon. Raptors were infected by Haemoproteus spp. (24% of 62 individuals), Leucocytozoon spp. (3% of individuals), and microfilaria (58% of individuals). Such new information from less-studied countries such as Iran can potentially be used to address conservation and management questions in epidemiological studies of wildlife diseases, veterinary medical treatment of captive birds, and in the investigation of host–parasite relationships.

High prevalence and genetic diversity of Haemoproteus columbae (Haemosporida: Haemoproteidae) in feral pigeons Columba livia in Cape Town, South Africa

In this study, we explore blood parasite prevalence, infection intensity, and co-infection levels in an urban population of feral pigeons Columba livia in Cape Town. We analyze the effect of blood parasites on host body condition and the association between melanin expression in the host’s plumage and parasite infection intensity and co-infection levels. Relating to the haemosporidian parasite itself, we study their genetic diversity by means of DNA barcoding (cytochrome b) and show the geographic and host distribution of related parasite lineages in pigeons worldwide. Blood from 195 C. livia individuals was collected from April to June 2018. Morphometric measurements and plumage melanism were recorded from every captured bird. Haemosporidian prevalence and infection intensity were determined by screening blood smears and parasite lineages by DNA sequencing. Prevalence of Haemoproteus spp. was high at 96.9%. The body condition of the hosts was negatively associated with infection intensity. However, infection intensity was unrelated to plumage melanism. The cytochrome b sequences revealed the presence of four Haemoproteus lineages in our population of pigeons, which show high levels of co-occurrence within individual birds. Three lineages (HAECOL1, COLIV03, COQUI05) belong to Haemoproteus columbae and differ only by 0.1% to 0.8% in the cytochrome b gene. Another lineage (COLIV06) differs by 8.3% from the latter ones and is not linked to a morphospecies, yet. No parasites of the genera Leucocytozoon and Plasmodium were detected.

Parasite burden in a short-lived chameleon, Furcifer labordi

Life history theory predicts that species with shorter lifespan should show higher investments into growth and reproduction at the expense of immune defenses. Labord's chameleon (Furcifer labordi) is the tetrapod with the shortest known life span. To investigate to which extent immunosenescence influences the die-off of these chameleons when they are only about 6 months old, we examined the gastrointestinal-, blood- and ectoparasite burden in F. labordi in Kirindy Forest (western Madagascar) and compared them with sympatric and longer living F. cf. nicosiai. Moreover, we included data from wild F. labordi that were singly housed under ambient conditions with daily food and water supply. Gastrointestinal parasite prevalence of wild F. labordi increased dramatically during the last 3 months of their lives, which include the reproductive period. Furcifer cf. nicosiai was found to have a belated increase in gastrointestinal parasites compared to F. labordi. In F. cf. nicosiai higher prevalence of blood parasites were found, which probably result from the longer exposure to the arthropod intermediate host. Both species showed infestations with ectoparasites, which peaked in the rainy season but disappeared towards the dry season. Male F. labordi showed a significantly higher prevalence of gastrointestinal - and ectoparasites and higher intensities of coccidians and ectoparasites than females. Males of F. cf. nicosiai exhibited higher prevalence of blood- and ectoparasites, as well as higher intensities in ectoparasites. Caged individuals of both sexes showed delayed senescence, reduced parasite burden and lived longer than their wild conspecifics. Overall, the increase in the prevalence in gastrointestinal - and blood parasites towards the disappearance of the wild population of F. labordi indicates that this species invests comparatively less energy in efficient immune system function, supporting the prediction of life history theory.

Migration distance does not predict blood parasitism in a migratory songbird.

Migration can influence host–parasite dynamics in animals by increasing exposure to parasites, by reducing the energy available for immune defense, or by culling of infected individuals. These mechanisms have been demonstrated in several comparative analyses; however, few studies have investigated whether conspecific variation in migration distance may also be related to infection risk. Here, we ask whether autumn migration distance, inferred from stable hydrogen isotope analysis of summer‐grown feathers (δ 2Hf) in Europe, correlates with blood parasite prevalence and intensity of infection for willow warblers (Phylloscopus trochilus) wintering in Zambia. We also investigated whether infection was correlated with individual condition (assessed via corticosterone, scaled mass index, and feather quality). We found that 43% of birds were infected with Haemoproteus palloris (lineage WW1). Using generalized linear models, we found no relationship between migration distance and either Haemoproteus infection prevalence or intensity. There was spatial variation in breeding ground origins of infected versus noninfected birds, with infected birds originating from more northern sites than noninfected birds, but this difference translated into only slightly longer estimated migration distances (~214 km) for infected birds. We found no relationship between body condition indices and Haemoproteus infection prevalence or intensity. Our results do not support any of the proposed mechanisms for migration effects on host–parasite dynamics and cautiously suggest that other factors may be more important for determining individual susceptibility to disease in migratory bird species.

Chronic stress in superb fairy‐wrens occupying remnant woodlands: Are noisy miners to blame?

AbstractInteractions between competing species may be intensified when they are restricted to small patches of remnant habitat, potentially increasing physiological stress in individuals. The effects of interspecific competition on stress in wildlife remain largely unexplored. In Australia, remnant woodlands are often dominated by aggressive honeyeaters, especially the noisy miner (Manorina melanocephala). Harassment of smaller birds by miners may result in their exclusion from suitable woodland habitat. We tested whether the presence of noisy miners is also associated with elevated stress in a model species of small passerine bird, the superb fairy‐wren (Malurus cyaneus). We sampled wrens from six sites, three remnant woodlands with noisy miners and three larger fragments of reserved habitat without noisy miners. Differential white blood cell counts were used to infer levels of chronic stress. We also assessed variation in body condition and the prevalence of blood parasites (Haemoproteus spp.) to test for associations between stress and parasitemia. The mean heterophil‐to‐lymphocyte (H:L) ratio was 1.8 × higher among superb fairy‐wrens living in miner‐dominated woodlands, suggesting higher levels of chronic stress. Individuals with higher stress appeared to be in poorer condition, as indicated by fat scores and residual body mass. Prevalence of blood parasites was generally high and was highest in reserved habitat (59%) where miners were absent. Birds with blood parasites living in these habitats had higher H:L ratios but the intensity of infection and H:L ratio was inversely related. Our results suggest that birds persisting in the presence of noisy miners might experience chronic stress, but further study is necessary to separate the relative importance of noisy miner aggression from other potential stressors in small patches of degraded woodland. Stress induced by interspecific aggression should be considered in future studies of wildlife living in remnant vegetation.