Serological investigation of Theileria sergenti using latex agglutination test in South Korea

Theileria sergenti causes persistent theileriosis in cattle, characterized by fever and chronic anemia. Theileriosis causes losses in feed efficiency and growth retardation through cycling infections in endemic areas. Among several major proteins of T. sergenti merozoites, the surface protein p33 is reported to be the most immunogenic. In this study, we investigated the use of p33 as a diagnostic antigen in a latex agglutination test to monitor antibodies against T. sergenti. When compared with TaqMan polymerase chain reaction, the sensitivity and specificity of the latex agglutination test were 86.5 and 92.5%, respectively. An epidemiological survey using the latex agglutination test was conducted with 1,046 sera collected from 4 slaughterhouses and 2 individual pasture farms throughout South Korea; 27.3% of samples were seropositive, depending on the areas in which the cattle were raised. This study indicated that the latex agglutination test could be used as a convenient tool for epidemiological monitoring of T. sergenti infections in the field.     

Expression of major piroplasm protein (p33) of Theileria sergenti (Korean isolate) and its immunogenicity in guinea pigs

To investigate the development of a subunit vaccine against theileriosis in cattle, the DNA fragments encoding piroplasm surface protein (p33) of Theileria sergenti of a Korean isolate were expressed in baculoviruses. The expressed p33 was characterized by indirect fluorescent antibody (IFA) and western blotting analysis. The expression of p33 was mainly detected on the surface of infected Sf21 cells by IFA. The immunoblotting analysis revealed the presence of a same molecular weight protein band of p33. The antigenicity of expressed polypeptide was further examined through the inoculation of a guinea pig. The sera of guinea pigs immunized with p33 expressed cell lysate showed similar fluorescent antibody patterns and reacted with the same molecular weight protein of T. sergenti in immunoblotting analysis, thus indicating that this protein can be a promising candidate for a subunit vaccine in the future.     

Theileria sergenti proliferates in SCID mice with bovine erythrocyte transfusion.

The unavailability of in vitro or in vivo experimental systems has been the major factor hampering the progress of research studies on Theileria sergenti, causative agent of theileriosis, a major disease of cattle in Japan. We report the first successful propagation of T. sergenti in SCID mice into which uninfected bovine erythrocytes (Bo-RBC) were supplied periodically. The infectivity of T. sergenti proliferated in an SCID mouse was ascertained by successful transfer of infection into another SCID mouse into which uninfected Bo-RBC were supplied periodically.     

Effects of bull exposure on the cyclic activity of beef cows

In Experiment I, 38 crossbred suckled beef cows grazing fescue pastures and 34 crossbred beef cows grazing bluestem pastures were randomly allocated at the time of calving into a group with 4 teaser bulls or no bulls. Two blood samples were collected 7 d apart from the cows to determine cyclic activity 67 and 76 d after calving in the fescue and bluestem pastures, respectively. Progesterone greater than 1.0 ng/ml in one or both samples indicated cyclic activity. There was no difference in the percentage of cows cyclic among the different groups. The number of cyclic cows in the fescue pasture with bulls was 16/19 (84%); in the fescue pasture with no bulls, 14/19 (74%); in the bluestem pasture with bulls, 17/17 (100%); and in the bluestem pasture with no bulls, 16/17 (94%). Overall cyclic activity among all cows for teaser bull-exposed and no bull was similar, 33/36 (91%) and 30/36 (83%). Overall cyclic activity was greater (P < 0.05) in cows grazing bluestem (33/34), 97% than fescue pastures (30/38), 80%. Measurements of cyclic activity were initiated too late in the postcalving period to quantify differences in estrous activity between the bull and no bull treatment groups. Another trial was planned for the following year with a modified protocol. In Experiment II, blood samples were collected for progesterone concentrations soon after calving and were repeated at intervals to characterize both the occurrence and duration of estrous cycles. In this experiment, 29 crossbred suckled beef cows grazing fescue pastures were randomly allocated 12 d after calving (Day 0) into 1 of 2 groups with teaser bulls or without bulls. Nineteen crossbred beef cows grazing bluestem pastures were allocated similarly 10 d after calving (Day 0). Bulls were added to the groups with bulls in fescue and bluestem pastures on day 6 after the initial allocations. Blood samples were collected from all cows on Day 0 and every 3 d until Day 46. Means (+/- SEM) of the cumulative progesterone concentrations (ng/ml) per cow for the 16 samples from cows grazing fescue were 12.5 +/- 3.5 for cows exposed to bulls, 2.5 +/- 0.16 for cows not exposed to bulls, 27.6 +/- 4.42 for cows grazing bluestem pastures and exposed to bulls, and 16.0 +/- 2.75 for cows without exposure to bulls. Progesterone concentrations were higher in cows exposed to bulls (P < 0.01). The percentages of both short and normal cycles increased (P < 0.01) in groups exposed to bulls (88%, 21/24 and 63%, 15/24) when compared with the no bull groups (29%, 7/24 and 21%, 5/24), respectively. Cows exposed to bulls also showed increased cyclic activity.     

Epidemiology of Tritrichomonas foetus in beef bull populations in Florida

The objectives of this study were to estimate the prevalence of herd and individual bull infection with Tritrichomonas foetus in a survey of beef bulls in the state of Florida and to perform an epidemiological investigation of risk factors for the disease. Bulls were tested for T. foetus colonization by a single preputial scraping and culture. Bull infection prevalence within herds was calculated and relationships with bull, herd factors, and production measurements were determined. The survey included 1984 beef bulls in 59 herds throughout Florida; nine bulls in three small herds (<100 cows) were later excluded from the models. An overall prevalence for T. foetus-infected bulls was 6.0% (within-herd prevalence ranged from 0 to 27%). The herd prevalence was 30.4% (i.e. at least one infected bull); infected bulls were found in 11.1 and 39.5% of herds sampled in North and South Florida, respectively. The likelihood of disease was greatest in larger herds in more extensive management settings (> or = 500 cows, 53.9% prevalence; medium-sized herds of 100-499 cows, 10.0% prevalence). Tritrichomonas foetus infection was associated with several bull factors, including age, breed, herd, and herd management practices (bull-to-cow ratio, bulls per breeding group). Tritrichomonas foetus infection continues to be prevalent in beef herds in Florida that use natural service.     

Grazing behaviour and performance of lactating suckler cows, ewes and goats on partially improved heathlands

The foraging behaviour (grazing time and diet composition), live-weight (LW) changes and parasitic infection (faecal egg counts of gastrointestinal nematodes) of 12 beef cows, 84 ewes and 84 goats suckling their offspring, managed in mixed grazing on heathlands with 24% of improved pasture of perennial ryegrass-white clover, were studied during the years 2003 and 2006. The results showed that goats tended to graze for a longer time, and utilised significantly more heathland vegetation than cattle and sheep, including in their diet in an average of 0.39 herbaceous plants, 0.11 gorse and 0.51 heather over the grazing season, comparing with respective mean values of 0.85, 0.02 and 0.13 in cattle and sheep. Dietary overlap was higher between cattle and sheep (0.76) than between sheep and goats (0.53) or between cattle and goats (0.47). Despite the high performance of autumn-calving cows in spring, sheep had the best LW changes per livestock unit (LU) during the whole grazing season. Goats' performance per LU was lower than in sheep but higher than in spring-calving cows. Regarding offspring production, lambs had higher LW gains per LU than calves and kids. Mean nematode eggs/g fresh faeces (epg) during the grazing season were higher in goats (91 epg) compared with sheep (34 epg) and cattle (14 epg), particularly from September to December. In conclusion, sheep performed best on these heathlands with improved pasture areas if the entire grazing season was considered, despite the good level of production in spring from autumn-calving cows. The results suggested the complementary use of goats in order to increase the effective utilisation of the available vegetation, achieving production levels similar to those from spring-calving cows. Therefore, mixed flocks of sheep and goats would be the most appropriate sustainable systems from the animal production and vegetation use points of view.     

Flow cytometry to evaluate Theileria sergenti parasitemia using the fluorescent nucleic acid stain, SYTO16

BACKGROUND: Although the infection of Theileria sergenti is demonstrated by intraerythrocytic localization of this parasite, much time and labor are necessary in order to determine this. We applied flow cytometry to evaluate T. sergenti parasitemia using the fluorescent nucleic acid stain method. METHODS: Peripheral blood samples from cattle infected with T. sergenti were stained with a membrane-permeable fluorescent nucleic acid stain, SYTO16, and hydroethidine (HE). Stained parasitized erythrocytes were measured by a flow cytometer equipped with a single argon laser operating at 488 nm. RESULTS: SYTO16-stained intraerythrocytic parasites were detected on the FL1 (525 nm) and parasitized cells were separated completely from unparasitized cells. However, HE-stained erythrocytes could not be divided clearly into parasitized and unparasitized cells. SYTO16-stained parasites were reproducibly detected at a percentage above 0.1%. Contaminating leukocytes, which were indicated by CD18-positive cells, were eliminated from the analysis by narrowing the light scatter gate of the erythrocyte fraction. A correlation (r = 0.983) between the percentage of SYTO16-positive cells and parasitemia in grazing cattle was observed. CONCLUSIONS: Flow cytometric detection using SYTO16 is a rapid and reliable method of monitoring parasitemia in T. sergenti-infected cattle.     

Prevalence of Carriage of Shiga Toxin-Producing Escherichia coli Serotypes O157:H7, O26:H11, O103:H2, O111:H8, and O145:H28 among Slaughtered Adult Cattle in France

The main pathogenic enterohemorrhagic Escherichia coli (EHEC) strains are defined as Shiga toxin (Stx)-producing E. coli (STEC) belonging to one of the following serotypes: O157:H7, O26:H11, O103:H2, O111:H8, and O145:H28. Each of these five serotypes is known to be associated with a specific subtype of the intimin-encoding gene (eae). The objective of this study was to evaluate the prevalence of bovine carriers of these “top five” STEC in the four adult cattle categories slaughtered in France. Fecal samples were collected from 1,318 cattle, including 291 young dairy bulls, 296 young beef bulls, 337 dairy cows, and 394 beef cows. A total of 96 E. coli isolates, including 33 top five STEC and 63 atypical enteropathogenic E. coli (aEPEC) isolates, with the same genetic characteristics as the top five STEC strains except that they lacked an stx gene, were recovered from these samples. O157:H7 was the most frequently isolated STEC serotype. The prevalence of top five STEC (all serotypes included) was 4.5% in young dairy bulls, 2.4% in young beef bulls, 1.8% in dairy cows, and 1.0% in beef cows. It was significantly higher in young dairy bulls (P < 0.05) than in the other 3 categories. The basis for these differences between categories remains to be elucidated. Moreover, simultaneous carriage of STEC O26:H11 and STEC O103:H2 was detected in one young dairy bull. Lastly, the prevalence of bovine carriers of the top five STEC, evaluated through a weighted arithmetic mean of the prevalence by categories, was estimated to 1.8% in slaughtered adult cattle in France.     

The influence of oxidative bursts of phagocytes on red blood cell oxidation in anemic cattle infected with Theileria sergenti

The primary clinical symptom of Japanese bovine theileriosis, caused by the intraerythrocytic protozoan Theileria sergenti, is anemia, but the underlying mechanism of this anemia remains unknown. To elucidate the pathogenesis of anemia developing in bovine theileriosis, we investigated the relationship between oxidative bursts of peripheral blood phagocytes (neutrophils and monocytes) and the oxidation of red blood cells (RBC) to the development of anemia in cattle experimentally infected with T. sergenti. The levels of methemoglobin (MetHb) and malondialdehyde (MDA), as a parameter of intracellular and membrane oxidative damage in RBC and of production of hydrogen peroxide (H2O2) in phagocytes, were low before the onset of anemia; these parameters began to increase remarkably with decreasing packed cell volume and increasing parasitemia during the course of the anemia, which returned to initial levels during convalescence from anemia. A positive correlation between H2O2 production of phagocytes and each of the oxidative indices of MetHb and MDA was also noted during the onset of anemia. The levels of antioxidants, namely reduced glutathione and glucose-6-phosphate dehydrogenase, in RBC also decreased during the progression of anemia. These results suggest that oxidative damage of RBC has a close relationship with the onset of anemia in bovine theileriosis, and that oxidative bursts of phagocytes may play a part in the pathogenesis of anemia in infected cattle.     

Effect of gonadotrophin releasing hormone on conception rate in repeat-breeder dairy cows

The effect of gonadotrophin releasing hormone (GnRH) on conception rate was studied in 961 repeat-breeder cows in five California dairy farms. Cows were injected with GnRH or saline at the time of the fourth insemination. All breeding was by artificial insemination (AI) using frozen semen from two bulls. Conception rate for GnRH-treated cows was higher than for controls (47.0 vs 37.7%, P < 0.01). There was no significant difference in conception rate between the two bulls or among five AI technicians. How GnRH acts upon fertility in repeat-breeder cattle has not been determined.     

Tick-borne diseases of livestock in Italy: general review and results of recent studies carried out in the Apulia region

This paper reviews basic information on the knowledge of tick-borne diseases, babesiosis, anaplasmosis and theileriosis, in horses, cattle, sheep and goats in Italy with particular reference to the southern part of the country. It is stressed that there is limited knowledge about the parasite species present, their vectors, distribution, prevalence and impact on livestock production and there is the need to assess their epidemiology. A study carried out in the Apulia region to assess the prevalence of Anaplasma marginale infection in 1,648 cattle showed a seroprevalence of 17% using the Card Agglutination Test. In another study in the same region a microscopic prevalence of 78% for Theileria spp. was found in 60 cows. Afterwards using the IFAT test the Theileria sp. was identified as Theileria buffeli/orientalis.     

Tick-borne diseases in ruminants of Central and Southern Italy: epidemiology and case reports

Sera and blood from cattle and sheep were examined for the presence of Babesia and Theileria spp by microscopy and serology at the Parasitology Department of the Istituto Zooprofilattico Sperimentale of Abruzzo and Molise (IZSAM). Of the 47 bovine herds (323 animals) tested, 15 were found positive for Babesia bigemina and 1 for Babesia bovis. Two outbreaks occurred, one caused by B. bigemina and one by B. bovis. The B. bigemina outbreak occurred in Abruzzo and has been followed for two years. The isolate of B. bigemina was very pathogenic leading to the death of two cows out of 57. The vector responsible of the transmission appeared to be Rhipicephalus bursa. Parasites were observed in the erythrocytes for 30 days whereas sera were positive to indirect immunofluorescence (IFA) for at least one year. The B. bovis outbreak occurred in the province of Mantova (Northern Italy) in a group of 70 beef cattle imported from France. The infection resulted in the death of 5 animals and severe illness in another 6. In contrast with what occurred for Babesia infection, no clinical cases were recorded in cattle when species of Theileria were detected by microscopy. Of the 24 bovine herds (252 animals) tested for Theileria, 21 were found positive for the T. "sergenti"/buffeli/orientalis group. Single and mixed infection of T. "sergenti" and T. buffeli/orientalis were detected in herds of cross-bred cattle from Abruzzo and Marche. The parasites were identified by using a polymerase chain reaction which amplified DNA encoding p32/34. Most of the collected ticks (90%) were adults of R. bursa whereas the others were adults of Hyalomma detritum. During the period the animals have been observed (18 months), no clinical cases have been recorded and no associations have been found between blood abnormalities and animals found infected with Theileria. Prevalences of subclinically infected carriers increased from February till December (95.4%) even if the animals were indoors and no ticks were present. The prevalence then dropped dramatically six months later (76.7%). In calves less than 1 year old, the prevalence of infection significantly (p<0.05) increased with age, however intraerythrocytic stages of Theileria were found in the blood of three newborn calves (<7 days of age). Of the 18 ovine flocks tested for Babesia spp. (150 animals examined), 1 was positive for B. ovis and 2 for B. motasi. B. motasi infection was not associated with symptoms, while an outbreak of babesiosis caused by B. ovis occurred in Abruzzo. The infection resulted in the death of 3 animals (0.75% of the flock), two rams (20% of the total number) and a ewe, and severe illness in another 5 ewes (2% of the flock). Specimens of R. bursa and R. turanicus were collected from the infected animals. Of the 18 flocks (150 animals) examined, 12 were microscopically positive for Theileria spp. No clinical cases were recorded and identification at species level was not possible on the basis of morphological criteria. The prevalence distribution of infected herds and infected animals within herds and flocks have been calculated by a Monte Carlo simulation model, running 10,000 iterations. The most likely levels of prevalence of infected herds and infected animals within herds found for the species observed were as follows: 20% for B. bigemina with a prevalence within herd of 27%, 11% for B. bovis (18% within herd), 10% for Babesia ovis (19% within herd), 10% for B. motasi (17.5% within herd), 63% for Theileria in cattle (66% within herd) and 51% for Theileria in sheep (55% within herd).     

Identification of complex vertebral malformation carriers in Holstein cattle in south China

Complex vertebral malformation (CVM) is a recently described monogenic autosomal recessive hereditary defect of Holstein dairy cattle that causes premature birth, aborted fetuses and stillborn calves. Guanine is substituted by thymine (G>T) in the solute carrier family 35 member A3 gene (SLC35A3). A valine is changed to a phenylalanine at position 180 of uridine 5'-diphosphate-N-acetyl-glucosamine transporter protein. CVM is expected to occur in many countries due to the widespread use of sire semen. We developed a created restriction site PCR (CRS-PCR) method to diagnose CVM in dairy cows. This was tested on 217 cows and 125 bulls selected randomly from a Holstein cattle population in south China. Five Holstein cows and five Holstein bulls were identified to be CVM carriers; the percentages of CVM carriers were estimated to be 2.3, 4.0 and 2.9% in the cows, bulls and entire Holstein cattle sample, respectively.     

Diet selection and performance of cattle and horses grazing in heathlands

As the number of horses is steadily increasing in Cantabrian less-favoured areas, mostly occupied by nutritionally poor heathland communities, the objective of this research was to study and compare diet selection and performance of crossbred horses and beef cattle (Asturiana de los Valles breed) grazing these areas during the summer. A total of 20 cows (seven lactating their calves and thirteen dry) and 20 mares (eight lactating their foals and twelve dry) were managed during 3 years on a heathland area from June to September and October. The proportion of grass (mostly Pseudarrhenatherum longifolium) and heather (Erica umbellata, E. cinerea and Calluna vulgaris) in the diet selected by cows and mares was estimated in two occasions (July and September) each year using the alkane markers. All animals were weighed at the beginning, middle and end of the summer grazing season. Mares selected heath grasses and rejected heather species more than did the cows (P < 0.001), particularly in early summer (0.85 v. 0.65 herbage proportion in July; 0.63 v. 0.55 in September). Lactating state did not affect diet composition. Mares achieved more favourable (P < 0.001) body weight (BW) changes than cows, but there was also an interaction with season (P < 0.001). From June to August, cows lost BW, being the daily changes (in percentage of initial BW) -0.15%/day in lactating and -0.05%/day in dry cows, whereas both lactating and dry mares gained BW (0.16 and 0.12%/day, respectively). From August to October, lactating cows and mares lost more BW (P < 0.01) compared with their non-lactating counterparts (-0.19 v. -0.10%/day in cows, -0.14 v. -0.05%/day in mares). With regard to the offspring, BW gains between June and August were similar in calves and foals (0.83 and 0.90%/day, respectively), but thereafter calves achieved higher (P < 0.05) BW gains than foals (0.37 v. 0.16%/day). It is concluded that the low nutritive quality of these heathlands restricts, both cattle and horse performance, even during short summer grazing season, being more penalized lactating animals, especially the cows. Although calves were able to maintain acceptable growth rates, foals showed reduced ones during the second half of the grazing season. Other plant communities with better nutritive quality should be provided to assure replenishment of body reserves in dams, and enhance offspring gains to maintain sustainable grazing systems with productive herds of cattle and horses in these heathland areas.     

Polymorphism analysis of Chinese Theileria sergenti using allele-specific polymerase chain reaction of the major piroplasm surface protein gene

Theileria sergenti is a tick-borne parasite found in many parts of the world. The major piroplasm surface protein (MPSP), a conserved protein in all Theileria species, has been used as a marker for epidemiological and phylogenetic studies of benign Theileria species. In this study, Chinese species of T. sergenti were characterized by allele-specific polymerase chain reaction (PCR) and DNA sequence analysis of the MPSP gene. Using universal or allele-specific primer sets for PCR amplification of the MPSP gene, 98 of 288 cattle blood samples, collected from 6 provinces in China, were found to be positive. Among the positive samples, only 3 allelic MPSP gene types (Chitose [C]-, Ikeda [I]-, and buffeli [B]-type) were successfully amplified. Moreover, the results revealed that the majority of the parasites sampled in this study were C- and I-type (prevalence of 84 and 69%, respectively), whereas the B-type was less common (prevalence of 36%). Co-infections with C-, I-, and B-type T. sergenti also were found. An additional known allele, Thai-type, was not detected. Phylogenetic analysis based on the MPSP gene sequences, including 3 standard stocks generated in the laboratory ( T. sergenti Wenchuan, T. sergenti Ningxian, and T. sergenti Liaoyang), revealed that the isolates of Chinese sergenti were comprised of at least 4 allelic MPSP gene types, i.e., C-, I-, B1-, and B2-type, and these parasites with 6 MPSP types 1-5 and 7 were present in China.     

Control of Theileria annulata in Iran

Tropical theileriosis or Mediterranean Coast Fever - caused by Theileria annulata - is a disease of cattle widely distributed across southern Europe, north Africa and central Asia. Its distribution broadly corresponds with that of its main ixodid tick vectors Hyalomma excavatum and H. detritum (Fig. 1). 'Exotic' cattle (Bos taurus) are particularly susceptible with mortalities up to 40-80% in some areas, whereas indigenous cattle (B. indicus) generally suffer much lower mortalities (about 10%) confined mainly to calves. But because imported non-immune cattle are so susceptible, T. annulata represents a major constraint to livestock improvement programmes in many parts of the middle east and Asia. Cattle that recover from T. annulata infection generally show a solid, long-lasting immunity. For many years there have been programmes to protect cattle by inoculation with blood from sick animals, and more recently using live attenuated T. annulata vaccines prepared from cultured schizont-infected lymphoid cells. This article reviews a 14 year immunization programme against T. annulata in Iran.     

Spatial variation of tick abundance and seroconversion rates of indigenous cattle to Anaplasma marginale, Babesia bigemina and Theileria parva infections in Uganda

Tick abundance and seroconversion rates of 640 indigenous cattle in a mixed crop-livestock system in Uganda were investigated in a 14 months longitudinal study. Up to 100% of the cattle in Buyimini, Kubo, Nanjeho, Ojilai and Sitengo villages (high tick challenge zone) were consistently infested with Rhipicephalus appendiculatus, whereas on average 50% of the cattle in Bunghaji, Hitunga and Magoje villages (low tick challenge zone) were inconsistently infested. Likewise, up to 50% of the cattle in Buyimini, Kubo, Nanjeho, Ojilai and Sitengo villages were consistently infested with R. (Boophilus) decoloratus ticks, while on average 30% of the cattle in Bunghaji, Hitunga and Magoje were inconsistently infested. Seroconversion rates of cattle to Anaplasma marginale infection under low tick challenge were higher than those under high tick challenge, but the reverse was true for Babesia bigemina infection. For Theileria parva infection, seroconversion rates of cattle older than 6 months under low tick challenge were significantly higher than those under high tick challenge (P < 0.05). However, the likelihood of occurrence of theileriosis cases among calves (0-6 m) under high tick challenge was 6 times (Odds ratio = 5.82 [1.30-36.37]) higher than under low tick challenge. The high density of anti-tick plants Lantana camara and Ocimum suave that were widespread in villages with low tick challenge, among other factors, was probably the cause for unfavourable tick survival.     

Thelazia rhodesii (Desmarest, 1828) in cattle of Central Province, Zambia

Sanga cattle from Central Zambia were examined during the dry and the rainy seasons for the presence of the adult stage of eyeworm Thelazia rhodesii. Prevalences were recorded according to age/sex groups. The occurrence of ocular diseases was also noted. Differences between the total prevalences of infection with the parasite in the dry and rainy seasons were observed: respectively 3.1% and 26.6% of all cattle examined (p less than 0.001), which numbered 223 head in the dry season and 248 in the rainy season. In both seasons, adult males showed the highest prevalence and calves the lowest. In the dry season the parasite was found in two of the 23 males (8.7%) but in none of the 24 calves. During the rains, eight of the 22 adult males (36.4%), and two of 53 calves (3.8%) were parasitized (p less than 0.001). A comparison of the prevalences in the latter season between a group of cows sprayed weekly with a synthetic pyrethroid and an untreated group showed no significant difference between the two groups (p greater than 0.1). No correlation was found between T. rhodesii infection and the occurrence of eye lesions (p greater than 0.1). It is concluded that in traditionally managed Zambian cattle the infection is seasonal, is more frequent in adult male animals and is not associated with eye infections (i.e., pink-eye).     

Detection of natural infections with Theileria annulata on calves at first theileriosis season: comparison of the Indirect Fluorescent Antibody Test (IFAT) and blood smears

The Indirect Fluorescent Antibody Test (IFAT) remains so far the most commonly used test for sero-epidemiological investigations on tropical theileriosis (infection of cattle with Theileria annulata). The present studies evaluated the ability of both IFAT with schizont antigen (schizont IFAT) and blood smears to detect infected animals just after the theileriosis season. This evaluation was performed on a group of 89 calves of known infection status for T. annulata at first disease season, from farms with endemic stability for tropical theileriosis. An additional retrospective group of 84 cattle free of infection was also used for the estimation of the specificity of the schizont IFAT. The sensitivity and the specificity of schizont IFAT were 88.9% (64/72) and 97% (98/101), respectively. Blood smears showed a lower sensitivity of 63.9% (46/72). The agreement between the two detection techniques and the infection status of the animals, evaluated by the Kappa coefficient, was 0.85 and 0.64 for IFAT and blood smears, respectively.