Haemoparasitic Infections Research Articles

Molecular and microscopic detection of haemoprotozoan diseases in dogs from Haryana, India.

Haemoparasitic infections are frequently observed in dogs from tropical regions, including India. The present investigation combined microscopic blood smear examination and PCR assays to assess the occurrence of canine tick-borne diseases (CTBD) from suspected dogs in and around Hisar, Haryana. Using the Giemsa-stained peripheral thin blood smear examination, 15 (12.5%) of the 120 dogs were infected with CTBD, with 5.8%, 3.3%, 2.5%, and 0.8% dogs testing positive for Hepatozoon canis, Ehrlichia canis, Babesia vogeli, and Babesia gibsoni, respectively. Using the PCR assay, CTBD was found to be 64.16% (77/120) in examined dogs. Of the 77 PCR-positive canines, 56 were infected with a single haemoparasite, while 21 were infected with two or more species. H. canis was the most abundant tick-borne pathogen, representing 35%, followed by E. canis 25.8%, B. vogeli 20%, and B. gibsoni 2.5%. The most common co-infection was with H. canis along with E. canis (7.5%). The PCR assay was proven to be more efficient for detecting haemoparasites in dogs compared to blood smear examinations. The study suggests that canine tick-borne diseases are common in Haryana and recommends using PCR-based molecular tests in addition to conventional microscopic examination to diagnose these infections for effective treatment and management of infected canines.

Immune Mediated Haemolytic Anaemia Associated with Haemoparasitic Infections in Dogs

A haematological condition known as Immune-Mediated Haemolytic Anaemia (IMHA) affects dogs and is caused by antibodies directly destroying red blood cells in the bloodstream. It can be primary (idiopathic) or secondary (caused by neoplastic or infectious illnesses). An attack on circulating red blood cells by the immune system is the hallmark of IMHA, a potentially fatal autoimmune disease. Though the disease occurs naturally in both humans and dogs, it is significantly more prevalent in dogs. The aim of this review was to methodically assess the available data on the disease's clinico-pathology, its therapy and utilize the results to derive recommendations that may be implemented in broader veterinary medicine.

Prevalence of haemoparasites infection in diseased bovine and canine of Bhatinda district of Punjab, India.

Infections caused by tick-borne haemoparasites pose a significant global threat to both human and animal health. Within this category, various haemoparasites species belonging to genera like Anaplasma sp., Babesia sp., Ehrlichia sp., Hepatozoon sp., and Theileria sp., are particularly concerning due to their ability to cause diseases in a wide range of hosts, including mammals, birds, and reptiles. The present cross-sectional study involving 580 animals provides annual insights into the prevalence of major haemoparasites infections in the Bathinda region of Punjab. The observed trends indicate that haemoparasites infections were most common in cattle, followed by buffalo and canines. Risk factor analysis revealed that crossbreed cattle were more susceptible to infection, with a prevalence of 35.73% (95% CI 4.28-45.17). Amongst the cattle, adults exhibited a higher vulnerability to haemoparasites infections, with a prevalence of 35.89% (95% CI 5.50-33.64). Conversely, companion animals showed the opposite pattern, with a prevalence of 18.18% (95% CI 9.11-169.27). Furthermore, female dogs had a higher risk of haemoparasites infection, with a prevalence of 16.28% (95% CI 8.36-218.7). In light of these findings, it is imperative to emphasize early diagnosis, prompt antiprotozoals drug treatment, and effective control of tick vectors for the successful recovery of animals afflicted by haemoparasites infections.

Pleiotropic effects of melanin pigmentation: haemoparasite infection intensity but not telomere length is associated with plumage morph in black sparrowhawks.

There is increasing recognition of the potential pleiotropic effects of melanin pigmentation, particularly on immunity, with reports of variation in haemoparasite infection intensity and immune responses between the morphs of colour-polymorphic bird species. In a population of the black sparrowhawk (Accipiter melanoleucus) in western South Africa, light morphs have a higher haemoparasite infection intensity, but no physiological effects of this are apparent. Here, we investigate the possible effects of haemoparasite infection on telomere length in this species and explore whether relative telomere length is associated with either plumage morph or sex. Using quantitative polymerase chain reaction analysis, we confirmed that dark morphs had a lower haemoparasite infection intensity than light morphs. However, we found no differences in telomere length associated with either the haemoparasite infection status or morph in adults, although males have longer telomeres than females. While differences in haemoparasite intensity between morphs are consistent with pleiotropic effects of melanin pigmentation in the black sparrowhawk, we found no evidence that telomere length was associated with haemoparasite infection. Further work is needed to investigate the implications of possible pleiotropic effects of plumage morph and their potential role in the maintenance of colour polymorphism in this species.

<b>Prevalence of haemoparasitic infections and influencing factors among fighting bulls in Southern Thailand: A retrospective analysis</b>

Background: Haemoparasitic infections significantly threaten cattle health globally, leading to economic losses and welfare issues for farmers. Aim: This retrospective study aimed to investigate the prevalence and associated factors of haemoparasitic infections in fighting bulls in southern Thailand over an eight-year period. Methods: Laboratory records of 5,518 bulls from the Livestock Animal Hospital, Faculty of Veterinary Science, Rajamangala University of Technology Srivijaya, were reviewed for the period January 2016 to December 2023. Blood samples were analyzed using thin blood smear methods to identify haemoparasites, and packed cell volume was measured using the microhematocrit method. Detailed profiles and demographic data for each animal were recorded. Results: Among the fighting bulls, 323 (5.85%) tested positive for haemoparasitic infections, with five haemoparasites identified: Trypanosoma spp. (TP), Microfilariae, Anaplasma spp. (AP), Babesia spp. (BB), and Theileria spp. (TR). TP was the most prevalent at 2.90%. Bulls aged 1–5 years showed the highest infection rates at 7.04%, with a decline in infections as age increased. Annual trends peaked in 2018 at 8.80%, with significant yearly fluctuations for most parasites (P < 0.05) except AP and BB. Monthly analyses revealed the highest infection rates in March, particularly for TP, with significant monthly variations for TR (P < 0.05). Geographical differences in infection rates between the East and West coasts were minor and not statistically significant. However, seasonal variations were significant for BB and TR on the east coast during summer (P < 0.05). Bulls with PCV below 30% had a higher prevalence of haemoparasitic infections (8.06%) compared to those with PCV above 30% (5.87%), with significant differences in the prevalence of AP and TR infections (P < 0.05). Conclusion: This study adds to the understanding of haemoparasite infections in bulls, informing the development of educational materials for farmers and ultimately empowering them to make better herd health decisions.

Haemogram and blood cell morphological changes in haemoparasitic infection of poultry birds

Aim and Background: The poultry industry faces myriads challenges, necessitating effective management and control strategies. Thus, this study was designed to identify haemoparasite and determine the impact of haemoparasitic infection on blood cells and serum biochemical profiles in some poultry birds in Ibadan, Nigeria. Methods: The study examined 390 birds of different types and of various types for the prevalence and type of haemoparasites, haematological parameters, and associated risk factors. Thin smears were prepared from each bird and examined microscopically. Erythrocyte morphology, including size variation (anisocytosis), shape abnormalities (poikilocytosis), and other abnormalities were evaluated in the monolayer region of the smear. Results: The study found that 44.6% were infected with haemoparasites. Five species of hemoparasites were found during this study, including Plasmodium, Haemoparoteus, Leucocytozoon, Babesia and Microfilaria. In single infection Plasmodium spp was the most prevalent haemoparasite (51.72%) followed by Haemoproteus spp 3.45%, Babesia 3.45% and Microfilaria 1.72%. In mixed infection Plasmodium and Haemoproteus (19 %), Plasmodium and Microfilaria (8.62%), Babesia and Plasmodium (6.90%), Babesia and Haemoproteus (1.72%), Plasmodium and Leukocytozoon 1.72%, in triple infection Babesia, Haemoproteus and Plasmodium (1.72%). Infected birds showed significantly lower haematological parameters, with globulin and creatinine being crucial, while albumin was lower, and the difference between red blood cell diameters was not significant. Conclusion: The study reveals that haematological parameters and biochemical profiles in poultry birds are crucial indicators of their health and offer practical insights for poultry health management.

Prevalence and Haematobiochemical Changes Associated with Haemoparasitic Infection of Indigenous Pigeons (<i>Columba livia</i>) sold in Ibadan Market, Nigeria

Domestic pigeons are typically regarded as global birds and are great producers of meat and eggs. The presence of haemoparasites in birds causes serious health problems. The purpose of this study was to determine the prevalence of blood parasites and their impact on the haematological and biochemical profiles of pigeons in Nigeria. A total of 105 adult pigeon were randomly selected and purchased from Shasha, Bode and Molete live bird market in Ibadan. The screening for haemoparasites was done using a microscopic examination. The haematological parameters such as haemoglobin concentration, packed cell volume, red blood cell and total white blood cell counts were determined using haemocytometry. Spectrophotometry was also used to determine serum biochemicals such as albumin, aspartate aminotransferase, total protein, creatinine, glucose and blood urea nitrogen. The sampled pigeons had a 26% overall prevalence of haemoparasites, Single infection (Leucocytozoon spp (7.7%), Plasmodium spp (23.1%) and Haemoproteus spp (15.4%)) and Mixed infection (Leucocytozoon spp, Plasmodium spp and Haemoproteus spp (19.2%), Plasmodium spp and Haemoproteus spp (34.6%)). The haematological findings demonstrated a significant rise in heterophil, eosinophil, and monocyte of infected pigeons (p ≤ 0.05). According to the serum biochemical results, the levels of globulin, Aspartate transferase, Alanine aminotransferase, creatinine, and Blood Urea Nitrogen in infected pigeons had increased significantly (p ≤ 0.05). The prevalence of haemoparasites and their impact on blood parameters revealed their devastating effect on the avian hosts' immune systems, which makes parasitism on birds frequently have serious consequences. Therefore, it is advised that households in Ibadan, Nigeria, raising domestic pigeons implement vector control and prophylactic treatment.

Estimation of genetic parameters for the tick and hemoparasite burden in Angus cattle.

The study was conducted with the objective of estimating genetic and phenotypic parameters for tick (CRM) and Babesia bigemina (IBBi), Babesia bovis (IBBo), and Anaplasma marginale (IAM) burden in Angus female breed in Brazil. The sample group was composed of Angus females raised in herds located in a region of endemic instability for cattle tick fever in the state of Rio Grande Sul (RS), Brazil. The variance components were estimated using Bayesian inference and Gibbs sampling algorithm, considering a multi-trait animal model. Heritability estimates showed values of low magnitude, ranging from 0.03 (IBBo) to 0.16 (CRM), while repeatability estimates ranged between 0.07 (IBBo) and 0.21 (CRM). Regarding the genetic correlation estimates, the values showed low (-0.01 for IBBo × IAM) to moderate (0.55 between IBBi × IAM) magnitudes. The results indicate that it is possible to use tick count and hemoparasite infection levels as selection criteria, with small genetic gains.

Bird species with wider geographical ranges have higher blood parasite diversity but not prevalence across the African-Eurasian flyway

Avian blood parasites, from the genera Plasmodium, Haemoproteus and Leucocytozoon, are predicted to alter their range and prevalence as global temperatures change, and host and vector ranges shift. Understanding large-scale patterns in the prevalence and diversity of avian malaria and malaria-like parasites is important due to an incomplete understanding of their effects in the wild, where studies suggest even light parasitaemia can potentially cause rapid mortality, especially in naïve populations. We conducted phylogenetically controlled analyses to test for differences in prevalence and lineage diversity of haemoparasite infection (for Plasmodium, Haemoproteus and Leucocytozoon) in and between resident and migratory species along the African-Eurasian flyway. To test whether migratory strategy or range size drives differences in parasite prevalence and diversity between resident and migrant species, we included three categories of resident species: Eurasian only (n = 36 species), African only (n = 41), and species resident on both continents (n = 17), alongside intercontinental migrants (n = 64), using a subset of data from the MalAvi database comprising 27,861 individual birds. We found that species resident on both continents had a higher overall parasite diversity than all other categories. Eurasian residents had lower Plasmodium diversity than all other groups, and both migrants and species resident on both continents had higher Haemoproteus diversity than both African and Eurasian residents. Leucocytozoon diversity did not differ between groups. Prevalence patterns were less clear, with marked differences between genera. Both Plasmodium and Leucocytozoon prevalence was higher in species resident on both continents and African residents than in migrants and Eurasian residents. Haemoproteus prevalence was lower in Eurasian residents than species resident on both continents. Our findings contrast with previous findings in the North-South American flyway, where long-distance migrants had higher parasite diversity than residents and short-distance migrants, although we found contrasting patterns for parasite diversity to those seen for parasite prevalence. Crucially, our results suggest that geographic range may be more important than migratory strategy in driving parasite diversity within species along the African-Palaearctic flyway. Our findings differ between the three parasite genera included in our analysis, suggesting that vector ecology may be important in determining these large-scale patterns. Our results add to our understanding of global patterns in parasite diversity and abundance, and highlight the need to better understand the influence of vector ecology to understand the drivers of infection risk and predict responses to environmental change.

Prevalence of gastro-intestinal and haemoparasitic infections among domestic cats of Kerala.

The population of domesticated cats has drastically increased during the last decades. With the recently identified rise in cat population an upsurge in the parasitic infections associated with domestic cats is evident. A total of 122 domestic cats were screened for gastro-intestinal and haemoparasites. Screening for gastro-intestinal parasites revealed an overall prevalence of 19 per cent (23/122). Ancylostoma spp. was the major gastro-intestinal parasite noticed (61 per cent) followed by Toxocara cati (13.04 per cent), Isospora spp. (8.7 per cent), Diphyllobothrium latum (4.35 per cent) and mixed infection of these (13 per cent). Blood smear examination revealed Cytauxzoon spp. in three cats (2.46 per cent) and Babesia spp. in two cats (1.6 per cent). None of the cats were positive for gamonts of Hepatozoon spp. Molecular analysis revealed Hepatozoon spp. infection in seven cats (5.7 per cent), Cytauxzoon spp. in 29 cats (23.8 per cent) and Babesia spp. in two cats (1.6 per cent). Present study highlights the inevitability of molecular techniques in the identification of haemoparasites. Establishment of proper preventive measures are required to control parasitic infection among domestic cats.

Sexual differences in blood parasite infections, circulating carotenoids and body condition in free‐living red‐legged partridges

AbstractA central issue in avian ecology deals with the trade‐off between investment life‐history components, such as reproductive effort, and parasite and disease resistance. During reproduction, differences in the particular needs of males and females may further affect the outcome of such trade‐off. However, most studies performed to date on avian species have focused on males, while less is known about this subject in females. We investigated haemoparasite infections (genera Haemoproteus, Plasmodium and Leucocytozoon) in relation to sex, year, body condition and plasma concentrations of carotenoids in wild‐breeding Red‐legged partridges (Alectoris rufa). Our aim was to examine whether there are differences in infections between sexes and how parasite infections relate to carotenoid levels, physical condition and breeding parameters in non‐passerine wild birds. Males captured early in the breeding season were in better body condition than females, indicating a marked sexual difference in this trait in wild Red‐legged partridges. The prevalence of blood parasites in males was higher than in females. However, we found that females infected by blood parasites had lower plasma carotenoid concentrations than uninfected females, whereas no association between infection and carotenoid levels was found in males. This suggests sex‐related differences in the use of carotenoids to fight infections or for parasite resistance. A possible explanation of this contrasting pattern between sexes is that reproduction may not have to involve the same costs for males and females. We suggest that males would be under strong sexual selection and would trade health for signalling, which could simultaneously explain highest parasite prevalence being found in males and the contrasting patterns in blood carotenoid levels between males and females. Females in contrast, that were in worst body condition during early breeding season, were more sensitive to infections, diverting carotenoids to immune function more than males.

Hematologic parameters and the effect of hemoparasites of wild anurans in Northern Sinaloa, Mexico.

Few hematologic profiles for free-ranging amphibians are available. Hematologic evaluation is a useful tool for determining the health of amphibian populations and providing further knowledge for conservation actions. Hematologic variables and the presence and effect of hemoparasites in anuran species were evaluated in Northern Sinaloa, Mexico. Blood samples were collected from wild anurans of eight species to perform blood cell counts, leukocyte differential counts, and serum protein concentrations using manual methods and refractometry. In addition, morphologic identification and quantification of the hemoparasites were performed on blood smears. Differences were observed by sex, age, and season for the hematologic values of Incilius alvarius (n = 23), Incilius mazatlanensis (n = 46), Rhinella horribilis (n = 64), Leptodactylus melanonotus (n = 46), Lithobates forreri (n = 135), Lithobates catesbeianus (n = 20), Smilisca fodiens (n = 42), and Scaphiopus couchii (n = 7). Intra- and extra-erythrocytic hemoparasites were found in 56.2% of amphibian hosts; the hemoparasite infection of R. horribilis and L. melanonotus was higher in the dry season, showing increases in erythroplastids and monocytes. For L. forreri, males were more infected than females, and increases in leukocytes were associated with infections of different types of hemoparasites species. Hematologic values, hemoparasite prevalence, and the response to hemoparasite infection vary among amphibian species, sex, and age, as well as on season and hemoparasite type. This highlights the importance of hematologic evaluations in wild amphibian populations to determine the subclinical effects of hemoparasite infections.

Clinical, hematological and molecular evaluation of piroplasma and Anaplasma infections in small ruminants and tick vectors from Kurdistan province, western Iran

Tick-borne haemoparasite infections are a major challenge in small ruminant (SR) production across tropical areas. The present study evaluated the prevalence of Theileria, Babesia and Anaplasma in SRs and their tick vectors and estimated the association between pathogen prevalence with clinical hematological findings among SR populations in Kurdistan province, western Iran. In total, 250 blood samples and 250 tick species (one per animal) were collected from SR populations, along with clinical and hematological examinations. Microscopy of blood smears and molecular analysis were performed to detect potential infection with Theileria, Babesia and Anaplasma. Moreover, haemoparasites were explored in the isolated ticks using semi-nested PCR. Based on microscopy, the prevalence of Theileria, Anaplasma and Babesia infections was 91.2%, 23.2% and 2.4%, respectively. Semi-nested PCR analysis of blood samples demonstrated 86.8%, 78.8% and 14% prevalence for T. ovis, A. ovis and B. ovis, respectively. Dermacentor marginatus and Rhipicephalus turanicus were predominant isolated tick vectors from SR, while D. marginatus was the most contaminated tick in all investigated counties. There were, also, a statistically significant association between the estimated molecular prevalence rates with semi-yellow conjunctiva (A. ovis), body temperature (T. ovis and A. ovis), heart rate (T. ovis and B. ovis), mean white blood cell count (T. ovis and A. ovis), mean red blood cell count (T. ovis and B. ovis), as well as mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration in all haemoparasite infections. Future studies are recommended to reveal the epidemiology of such infections in SRs in Iran.

Analysis of the prevalence of infectious and immunosuppressive diseases in free-living cats in Moscow and the Moscow region

In cats living in urban environments, infectious and immunosuppressive diseases are observed with a similar symptom complex. Comprehensive analysis allows you to identify concomitant diseases that complicate the primary infection. In an experimental study in cats, diseases were diagnosed randomly based on clinical and anamnestic data, hematological and biochemical, immunological blood tests and PCR. All established diseases were conditionally divided into 5 groups: I - co-infections II - respiratory, III - gastroenterological, IV - chronic viral and V - hemoparasitic infections, toxoplasmosis, FIP. Group I included 96 cats with 2 or more viral agents from groups II-IV at the time of primary diagnosis; Group II included 92 animals; Group III - 70 cats; IV group - 16 cats; Group V - 9 animals. It follows from the statistical data that diseases caused by several infectious agents are most often recorded, the second most common are diseases of the respiratory system, and the third are diseases of the digestive system. The main problem of high infection with infectious and immunosuppressive diseases of cats is the crowded content of cat families in one area, with uncontrolled reproduction and spread of infections within a certain area; possible introduction of other strains or viruses through contact with cats from another population; replenishment of the virus population due to mutations during the death of individuals within the range.

Identification, molecular characterization and risk factors of Theileria infection among sheep: a first comprehensive report from North India

The present study was aimed at the identification, molecular characterization, and risk factor assessment of Theileria infection among sheep of Haryana province, north India. A total of 402 blood samples were collected from three different climatic zones of Haryana from March 2020 to September 2021. Light microscopy of blood smears revealed Theileria spp. infection in 47.26% (n = 190), while 60.94% (n = 245) of blood samples were positive using nested PCR. Extensive molecular characterization of Theileria infection using four pairs of species-specific primers indicated the dominance of T. ovis (29.1%) followed by T. lestoquardi (12.69%), T. luwenshuni (5.97%) and T. annulata (1.49%). Mixed infection was detected in 11.69% of cases. Bidirectional sequencing and phylogeny further confirmed the presence of these four Theileria spp. in the investigated area under study. Hematology indicated a significant (p < 0.01) reduction in various haematological indices of animals infected with T. luwenshuni and T. lestoquardi compared to the healthy control group. Risk factors like age, sex, and zone were significantly associated with Theileria infection in sheep. The present investigation depicts the first comprehensive molecular report of ovine Theileria spp., which warrants further study to develop suitable control strategies against these haemoparasitic infections.

Elucidating parasite and host-cell factors enabling Babesia infection in sickle red cells under hypoxic/hyperoxic conditions.

Sickle red blood cells (RBCs) represent a naturally existing host-cell resistance mechanism to hemoparasite infections. We investigate the basis of this resistance using Babesia divergens grown in sickle (SS) and sickle trait (AS) cells. We found that oxygenation and its corresponding effect on RBC sickling, frequency of fetal hemoglobin positive (HbF+) cells, cellular redox environment, and parasite proliferation dynamics, all played a role in supporting or inhibiting Babesia proliferation. To identify cellular determinants that supported infection, an image flow cytometric tool was developed that could identify sickled cells and constituent Hb. We showed that hypoxic conditions impaired parasite growth in both SS and AS cells. Furthermore, cell sickling was alleviated by oxygenation (hyperoxic conditions), which decreased inhibition of parasite proliferation in SS cells. Interestingly, our tool identified HbF+-SS as host-cells of choice under both hypoxic and hyperoxic conditions, which was confirmed using cord RBCs containing high amounts of HbF+ cells. Uninfected SS cells showed a higher reactive oxygen species-containing environment, than AA or AS cells, which was further perturbed on infection. In hostile SS cells we found that Babesia alters its subpopulation structure, with 1N dominance under hypoxic conditions yielding to equivalent ratios of all parasite forms at hyperoxic conditions, favorable for growth. Multiple factors, including oxygenation and its impact on cell shape, HbF positivity, redox status, and parasite pleiotropy allow Babesia propagation in sickle RBCs. Our studies provide a cellular and molecular basis of natural resistance to Babesia, which will aid in defining novel therapies against human babesiosis.

Association of single nucleotide polymorphisms in heat stress protein 70 (HSP70) and 90 (HSP90) with the susceptibility of Pakistani sheep breeds to hemoparasitic infections

The present study was designed to report the genotypic and allelic frequency of single nucleotide polymorphism (SNP) at 222 G > A in HSP70 and at ex6-7390T22G in the HSP90 gene of 204 sheep (Baluchi = 11, Kajli = 29, Latti = 06 and Mundri = 158) enrolled from District Rajanpur in Punjab and to report the susceptibility of these sheep to the blood-borne parasitic infection. The tetra-primer amplification refractory mutation system–polymerase chain reaction (T-ARMS–PCR) approach revealed a significant variation (p < 0.001) in the genotype frequency of four enrolled sheep breeds at SNP 222 G > A in the HSP70 gene while the allelic frequency remained unaffected (p = 0.08). In all sheep breeds, GG (wild) genotype was most common. T-ARMS–PCR analysis revealed a similar trend for ex6-7390T22G in the HSP90 gene and it was observed that sheep had significantly higher wild-type (GG) (p < 0.05) at the studied SNPs. Studied epidemiological factors (sex and sampling sites) were not found associated with both SNPs. Chi-square test revealed that no specific genotype and allelic frequency at 222 G > A in HSP70 and at ex6-7390T22G in the HSP90 gene of the enrolled sheep breed was associated with the susceptibility to blood-borne parasitic infection (p > 0.05). In conclusion, we are reporting that Pakistan is blessed to have majority of sheep, from all breeds, having wild genotype at analyzed SNPs in heat stress genes. We highly recommend the genotypic screening of sheep before their selection as breeders to reduce the possibility of having sheep with polymorphic genotypes at 222 G > A in HSP70 and at 7390T22G in HSP90 genes that will improve the profitability and sustainability of animal production systems in Pakistan.

Living with chronic infection: Persistent immunomodulation during avirulent haemoparasitic infection in a wild rodent.

Apicomplexans are a protozoan phylum of obligate parasites which may be highly virulent during acute infections, but may also persist as chronic infections which appear to have little fitness cost. Babesia microti is an apicomplexan haemoparasite that, in immunocompromised individuals, can cause severe, potentially fatal disease. However, in its natural host, wild field voles (Microtus agrestis), it exhibits chronic infections that have no detectable impact on survival or female fecundity. How is damage minimized, and what is the impact on the host's immune state and health? We examine the differences in immune state (here represented by expression of immune-related genes in multiple tissues) associated with several common chronic infections in a population of wild field voles. While some infections show little impact on immune state, we find strong associations between immune state and B. microti. These include indications of clearance of infected erythrocytes (increased macrophage activity in the spleen) and activity likely associated with minimizing damage from the infection (anti-inflammatory and antioxidant activity in the blood). By analysing gene expression from the same individuals at multiple time points, we show that the observed changes are a response to infection, rather than a risk factor. Our results point towards continual investment to minimize the damage caused by the infection. Thus, we shed light on how wild animals can tolerate some chronic infections, but emphasize that this tolerance does not come without a cost.

Prevalence of haemoparasites and influence on haemato-biochemical parameters of polo horses in Ibadan, Nigeria

Parasitic diseases, which can reside inside or outside the host, have a devastating impact on human and animal health worldwide, particularly in developing countries. Little is known about the current haemoparasitic status of polo horses in Ibadan, Nigeria. This study aims to find out the scope and extent of haemoparasites and their associated haematological and serum biochemical changes in polo horses in Ibadan, Nigeria. Blood samples were randomly collected from 52 horses from Ibadan polo stable. Haemoparasites identification, haematology and serum biochemistry parameters were evaluated according to standard procedures. The overall prevalence of haemoparasitic infection in the sampled horses was 13.5%. The haemoparasites found were Theileria equi (85.7%) and Anaplasma phagocytophilum (14.3%). The haematology result showed that infected horses presented a significant decrease (P&lt;0.05) in PCV, WBC counts and significant elevation (P&lt;0.05) of eosinophils. The serum biochemical values revealed that infected horses had significantly higher (P&lt;0.05) levels of AST and creatinine kinase whereas the glucose level was significantly lower (P&lt;0.05) when compared with the uninfected horses. To reduce the threat of haemoparasitic infection, it is recommended that vector control, as well as prophylactic therapy, be carried out in stables.

Identification and characterization of extracellular vesicles from red cells infected with Babesia divergens and Babesia microti.

Babesiosis is a zoonosis and an important blood-borne human parasitic infection that has gained attention because of its growing infection rate in humans by transfer from animal reservoirs. Babesia represents a potential threat to the blood supply because asymptomatic infections in man are common, and blood from such donors can cause severe disease in certain recipients. Extracellular vesicles (EVs) are vesicles released by cells that contain a complex mixture of proteins, lipids, glycans, and genetic information that have been shown to play important roles in disease pathogenesis and susceptibility, as well as cell–cell communication and immune responses. In this article, we report on the identification and characterization of EVs released from red blood cells (RBCs) infected by two major human Babesia species—Babesia divergens from in vitro culture and those from an in vivo B. microti mouse infection. Using nanoparticle tracking analysis, we show that there is a range of vesicle sizes from 30 to 1,000 nm, emanating from the Babesia-infected RBC. The study of these EVs in the context of hemoparasite infection is complicated by the fact that both the parasite and the host RBC make and release vesicles into the extracellular environment. However, the EV frequency is 2- to 10-fold higher in Babesia-infected RBCs than uninfected RBCs, depending on levels of parasitemia. Using parasite-specific markers, we were able to show that ~50%–60% of all EVs contained parasite-specific markers on their surface and thus may represent the specific proportion of EVs released by infected RBCs within the EV population. Western blot analysis on purified EVs from both in vivo and in vitro infections revealed several parasite proteins that were targets of the host immune response. In addition, microRNA analysis showed that infected RBC EVs have different microRNA signature from uninfected RBC EVs, indicating a potential role as disease biomarkers. Finally, EVs were internalized by other RBCs in culture, implicating a potential role for these vesicles in cellular communication. Overall, our study points to the multiple functional implications of EVs in Babesia–host interactions and support the potential that EVs have as agents in disease pathogenesis.