High 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.

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.

Host escape behavior and blood parasite infections in birds

Active and risk-taking behavior may bring animals into contact with predators but can also result in frequent encounters with parasites and vectors via the exploration of risky or diverse habitats. Therefore, we predicted that antipredator behavior, here measured as escape behavior when captured by a human, would correlate with risk of parasite infection at the interspecific level with bolder species having more parasites than risk-averse species. Here we tested whether species with more active escape behavior also tended to have high prevalence of blood parasites, specifically hemosporidian parasites. Focusing on effect sizes we found that escape behavior was intermediately and positively related to prevalence of infection with Haemoproteus and Leucocytozoon, whereas that was not the case for the more virulent Plasmodium. Species that were habitat generalists and hence encountered a greater diversity of habitats had higher prevalence of blood parasites than specialists. In addition, some components of escape behavior were correlated at an intermediate magnitude with habitat exploration, as reflected by the relative frequency of feeding innovations, and coloniality. We failed to find considerable patterns of correlations between most of the behavioral variables and flight initiation distance, another commonly used antipredator behavior. Therefore, behavioral responses to an approaching predator and to being caught by a human likely represent 2 independent axes of antipredator behavior that do not evolve in concert. These findings are consistent with the hypothesis that escape behavior is related to risk of infection with blood parasites partially mediated by the effect of habitat generalism.

Malaria infections reinforce competitive asymmetry between two Ficedula flycatchers in a recent contact zone

Parasites may influence the outcome of interspecific competition between closely related host species through lower parasite virulence in the host with which they share the longer evolutionary history. We tested this idea by comparing the prevalence of avian malaria (Haemosporidia) lineages and their association with survival in pied and collared flycatchers (Ficedula hypoleuca and F.albicollis) breeding in a recent contact zone on the Swedish island of Öland. A nested PCR protocol amplifying haemosporidian fragments of mtDNA was used to screen the presence of malaria lineages in 1048 blood samples collected during 6years. Competitively inferior pied flycatchers had a higher prevalence of blood parasites, including the lineages that were shared between the two flycatcher species. Multistate mark-recapture models revealed a lower survival of infected versus uninfected female pied flycatchers, while no such effects were detected in male pied flycatchers or in collared flycatchers of either sex. Our results show that a comparatively new host, the collared flycatcher, appears to be less susceptible to a local northern European malarial lineage where the collared flycatchers have recently expanded their distribution. Pied flycatchers experience strong reproductive interference from collared flycatchers, and the additional impact of species-specific blood parasite effects adds to this competitive exclusion. These results support the idea that parasites can strongly influence the outcome of interspecific competition between closely related host species, but that the invading species need not necessarily be more susceptible to local parasites.

Circannual variation in blood parasitism in a sub‐Saharan migrant passerine bird, the garden warbler

Knowing the natural dynamics of pathogens in migratory birds is important, for example, to understand the factors that influence the transport of pathogens to and their transmission in new geographical areas, whereas the transmission of other pathogens might be restricted to a specific area. We studied haemosporidian blood parasites of the genera Plasmodium, Haemoproteus and Leucocytozoon in a migratory bird, the garden warbler Sylvia borin. Birds were sampled in spring, summer and early autumn at breeding grounds in Sweden, on migration at Capri, Italy and on arrival and departure from wintering staging areas in West Africa: mapping recoveries of garden warblers ringed in Fennoscandia and Capri showed that these sites are most probably on the migratory flyway of garden warblers breeding at Kvismaren. Overall, haemosporidian prevalence was 39%, involving 24 different parasite lineages. Prevalence varied significantly over the migratory cycle, with relatively high prevalence of blood parasites in the population on breeding grounds and at the onset of autumn migration, followed by marked declines in prevalence during migration both on spring and autumn passage. Importantly, we found that when examining circannual variation in the different lineages, significantly different prevalence profiles emerged both between and within genera. Our results suggest that differences in prevalence profiles are the result of either different parasite transmission strategies or coevolution between the host and the various parasite lineages. When separating parasites into common vs. rare lineages, we found that two peaks in the prevalence of rare parasites occur; on arrival at Swedish breeding grounds, and after the wintering period in Africa. Our results stress the importance of appropriate taxonomic resolution when examining host-parasite interactions, as variation in prevalence both between and within parasite genera can show markedly different patterns.

Hidden haemosporidian infections in Ruffs (Philomachus pugnax) staging in Northwest Europe en route from Africa to Arctic Europe

In their African freshwater wintering habitats, shorebirds show a high prevalence of blood parasites, whereas no parasites are detected elsewhere along the migration route. We looked at two genera of haemosporidian parasites, Haemoproteus and Plasmodium, in the long-distance migrating Ruff (Philomachus pugnax) along a geographical/seasonal gradient to verify the infection pattern and examine possible hidden organ infections at European staging areas. We amplified parasite DNA from blood of 53 healthy birds wintering in Mali, 53 samples of seven organ tissues (spleen, liver, kidneys, heart, lungs, brain, and pectoral muscle) from healthy individuals caught during spring migration, and 18 weak birds found sick in summer in The Netherlands. We confirm that Ruffs wintering in Africa carried blood infections and that some infections developed into hidden organ infections during spring migration. Moreover, sick birds either had new infections (in one juvenile) or relapses (in an adult harboring an African lineage). Our results suggest that some parasites develop latency. This strategy may be beneficial for the parasite as it may take control over reappearance in the blood to help further transmission.

Infection by Haemoproteus Parasites in Four Species of Frigatebirds and the Description of a New Species of Haemoproteus (Haemosporida: Haemoproteidae)

Among seabirds, the fregatids stand out with a high prevalence of blood parasites. Four of 5 species in this family have been found to be infected with Haemoproteus; however, complete species descriptions with molecular phylogeny are lacking. Seventy-five samples from 4 species of frigatebirds, i.e., Fregata andrewsi, Fregata minor, Fregata magnificens, and Fregata aquila, were screened for infections caused by species of Haemoproteus. Four different parasite haplotypes were found infecting frigatebirds based on the sequencing of a fragment of the cytochrome b gene. Two haplotypes belong to the subgenus Parahaemoproteus, and the other 2 correspond to haplotypes within the subgenus Haemoproteus . The more prevalent and cosmopolitan Parahaemoproteus haplotype (FregPHae1) was phylogenetically grouped with other Haemoproteus parasites infecting non-passerine birds, but it could not be detected from the single sample from F. aquila. The other Parahaemoproteus haplotype (FregPHae2) was not phylogenetically clustered with parasites infecting non-passerine birds, and it was sequenced from a single (1 each) F. andrewsi and F. minor. Blood smears from F. andrewsi infected only by FregPHae1 haplotype showed sufficient gametocytes to allow description of a new species, Haemoproteus valkiūnasi sp. nov. In contrast to Haemoproteus iwa, the only previously known blood parasite infecting frigatebirds and described from F. minor from Galapagos Islands, parasites from F. andrewsi (1) are shorter with no contact of gametocyte with host cell membrane, (2) have fewer pigment granules, and (3) have wider microgametocytes, with a smaller host nuclear displacement. In contrast, patent single infections corresponding to the cosmopolitan haplotype of the subgenus Haemoproteus (FregHae1) were also found in samples from 1 F. andrewsi, 1 F. minor, and 1 F. aquila. In all these cases, the number of microgametocytes was very low, resembling H. iwa, which lacks microgametocytes in the original description. Macrogametocytes of haplotype FregHae1 in F. andrewsi differ significantly from all the characteristics measured from H. valkiūnasi. In addition, it also differs from all characteristics of H. iwa despite being genetically identical in the analyzed fragment.

High prevalence of blood parasites in social birds from a neotropical savanna in Brazil

Blood parasites play a fundamental role in the ecology and evolution of passerine birds because they are able to affect the fitness and survival of their hosts. The prevalence of avian malarial parasites among host species can vary from 0 to 100% but the ecological and evolutionary reasons for this variation are not clear. In this study we tested if height or type of nest, body mass or social system, which we believe are variables associated with exposure of hosts to vectors, could explain the variation in the prevalence of blood parasites in a bird community from the Cerrado biome of central Brazil. We found a significant positive correlation between nest-height and prevalence of Haemoproteus, which is consistent with the hypothesis linking prevalence of blood parasites with nesting stratum in North American birds. We also found evidence for increased levels of parasitism by Haemoproteus in neotropical birds that live in groups and breed cooperatively and increased levels of parasitism by Plasmodium in species that nest in cavities or closed cups. We suggest that reproductive and behavioural parameters of hosts may be responsible for their differential exposure to vectors and that these parameters may therefore be able to indicate interspecific variation in the prevalence of blood parasites in other bird communities.

Risk factors associated with both blood and internal parasites in dairy farms in kuku area, Khartoum state

Investigation of blood and internal parasites among different seasons (dry cool, dry hot and wet hot) in dairy herds in Kuku area of Khartoum State, revealed that there was a high prevalence of blood parasites in the dry cool season (46%) compared to dry hot and wet hot season (14.74% and 5.68%, respectively). While the presence of internal parasite was found to be less than infection with blood parasites (15%, 8.42% and 11.36 for dry cool, dry hot and wet hot season, respectively). A positive association (÷2=48.483, P0.05). Tick infestation was found statistically significant (÷2 = 20.583, P

MALARIA AND RISK OF PREDATION: A COMPARATIVE STUDY OF BIRDS

Predators have been hypothesized to prey on individuals in a poor state of health, although this hypothesis has only rarely been examined. We used extensive data on prey abundance and availability from two long-term studies of the European Sparrowhawk (Accipiter nisus) and the Eurasian Goshawk (Accipiter gentilis) to quantify the relationship between predation risk of different prey species and infection with malaria and other protozoan blood parasites. Using a total of 31 745 prey individuals of 65 species of birds from 1709 nests during 1977-1997 for the Sparrowhawk and a total of 21 818 prey individuals of 76 species of birds from 1480 nests for the Goshawk during 1977-2004, we show that prey species with a high prevalence of blood parasites had higher risks of predation than species with a low prevalence. That was also the case when a number of confounding variables of prey species, such as body mass, breeding sociality, sexual dichromatism, and similarity among species in risk of predation due to common descent, were controlled in comparative analyses of standardized linear contrasts. Prevalence of the genera Haemoproteus, Leucocytozoon, Plasmodium, and Trypanosoma were correlated with each other, and we partitioned out the independent effects of different protozoan genera on predation risk in comparative analyses. Prevalence of Haemoproteus, Leucocytozoon, and Plasmodium accounted for interspecific variation in predation risk for the two raptors. These findings suggest that predation is an important factor affecting parasite-host dynamics because predators tend to prey on hosts that are more likely to be infected, thereby reducing the transmission success of parasites. Furthermore, this study demonstrates that protozoan infections are a common cause of death for hosts mediated by increased risk of predation.

Ecological factors influencing disease risk in Eagle OwlsBubo bubo

In this study we assessed whether local habitat features and host population density influenced disease risk in Eagle OwlBubo bubofledglings. Measures of immune defence (concentrations of circulating white blood cells), prevalence of three parasite types (a blood parasiteLeucocytozoon ziemanni, an insectCarnus haemapterus, and a tickRhipicephalussp.) and total number of parasite species were used to quantify disease risk. We tested the hypotheses that disease risk in fledglings was higher in nests located in areas with higher length of and proximity to watercourses (as a higher abundance and viability of parasites and vectors occur in wetter areas), higher cover of forest (as forest moistness and humidity can favour higher vector and parasite proliferation), higher habitat diversity (as environmental heterogeneity increases the pool of potential vectors and parasites) and higher local owl population density (as disease transmission might be density‐dependent). The clearest relationship was with the proximity of freshwater, although the other hypotheses were also partially supported. Concentrations of white blood cells, the number of parasite species and, weakly, the prevalence ofCarnus haemapteruswere all higher in nests closer to watercourses. The prevalence of blood parasites increased with the cover of forested areas. Fledglings from nests located in more diverse habitats had higher white blood cell concentrations and showed higher prevalence of blood parasites. Finally, local host population density was positively correlated with the prevalence of blood parasites. The results suggest the existence of complex and interrelated links between ecological parameters and three different measures of disease risk, and highlight the importance of immunological approaches to assess disease risk at an intraspecific level.

Migratory Movements of Sharp-Shinned Hawks (Accipiter Striatus) Captured in New Mexico in Relation to Prevalence, Intensity, and Biogeography of Avian Hematozoa

Abstract Previous interspecific studies have shown that migratory birds have a higher prevalence of blood parasites than nonmigratory birds. It is thought that birds that move greater distances are exposed to a larger parasite fauna, because of uneven distribution of vectors that carry such parasites. Current hypotheses also suggest that the stress of migration may allow parasites to persist, by weakening the immune system and allowing latent infections to recur. We captured migrating hatching-year Sharp-shinned Hawks (Accipiter striatus) in New Mexico and estimated natal latitudes of each individual by analyzing stable-hydrogen isotope ratios of feathers. That enabled us to estimate distances traveled up to point of capture. We also collected blood to quantify hematozoan infection prevalence and intensity. We related distance traveled to prevalence and intensity of hematozoan infections. Contrary to previous hypotheses, our results show no relationship between distance traveled by migrants and prevalence and intensity of hematozoan infections. Of 75 individuals examined, 24% were infected with Leucocytozoon toddi, 37% with Haemoproteus elani, and 5% with H. janovyi. To our knowledge, this is the first documented occurrence of H. janovyi in North America and in Sharp-shinned Hawks. Our stable-hydrogen isotope analyses indicated that H. janovyi was detected only in birds that originated in southwestern North America, which may be of significance in regard to biogeography of that parasite species.

PARASITISM, IMMUNITY, AND ARRIVAL DATE IN A MIGRATORY BIRD, THE BARN SWALLOW

Long-distance bird migration is expensive, and individuals in prime condition are therefore expected to arrive at the breeding grounds earlier than the average individual in the population. We tested whether arrival date during spring migration was associated with low parasite burden and strong T-cell-dependent immune response in populations of the transequatorially migrating Barn Swallow Hirundo rustica from Denmark, Italy, and Spain. Male Barn Swallows with heavy infestations of the chewing louse Hirundoecus malleus L. arrived later than other males, whereas that was not the case for females. This negative relationship remained after controlling the relationship between parasite load and arrival for tail length. Infection with blood parasites of the species Haemoproteus prognei was associated with delayed arrival in the Spanish population, which was the only one with a high prevalence of blood parasites. High intensities of infestation with a commensal feather mite were associated with early arrival by females, but also by males when the independent relationship between tail length and intensity of mite infestation was controlled statistically. Experimental manipulation of nest infestation with the hematophagous mite Ornithonyssus bursa Berlese affected the arrival date of adult males, but not of females in the following year, with arrival date being inversely related to the experimental mite population size. Males with strong T-cell responses arrived earlier than males with weak responses, independent of their tail length in two of three populations, but there was no significant relationship in females. These findings are in accordance with predictions based on the hypothesis that bird migration is dependent on condition, with individuals in prime condition arriving early.

MIGRATORY MOVEMENTS OF SHARP-SHINNED HAWKS (ACCIPITER STRIATUS) CAPTURED IN NEW MEXICO IN RELATION TO PREVALENCE, INTENSITY, AND BIOGEOGRAPHY OF AVIAN HEMATOZOA

Abstract Previous interspecific studies have shown that migratory birds have a higher prevalence of blood parasites than nonmigratory birds. It is thought that birds that move greater distances are exposed to a larger parasite fauna, because of uneven distribution of vectors that carry such parasites. Current hypotheses also suggest that the stress of migration may allow parasites to persist, by weakening the immune system and allowing latent infections to recur. We captured migrating hatching-year Sharp-shinned Hawks (Accipiter striatus) in New Mexico and estimated natal latitudes of each individual by analyzing stable-hydrogen isotope ratios of feathers. That enabled us to estimate distances traveled up to point of capture. We also collected blood to quantify hematozoan infection prevalence and intensity. We related distance traveled to prevalence and intensity of hematozoan infections. Contrary to previous hypotheses, our results show no relationship between distance traveled by migrants and prevalence...

Ornithophilic vectors of avian hematozoa in insular Newfoundland.

Ornithophilic vectors of avian hematozoa on the Avalon Peninsula, Newfoundland, were determined to be Simulium latipes and S. aureum for Leucocytozoon, Culicoides stilobezzioides for Haemoproteus, and possibly, on circumstantial evidence, Aedes punctor for Plasmodium. Simuliids and ceratopogonids were captured following attraction to bird bait most frequently at heights of 3–4 m in the forest canopy, in the evening, during July and August. Vector density was extremely low when compared to elsewhere in North America, but the highly efficient host–vector–parasite relationship maintained a high prevalence of blood parasites in the bird population.