Shawkat Q. Lafi

EQUINE BABESIOSIS ASSOCIATED WITH STRENUOUS EXERCISE : CLINICAL AND PATHOLOGICAL STUDIES IN JORDAN

Clinical, haematological and pathological studies were undertaken in Jordan in a stud of 103 racing horses clinically suffering from babesiosis and apparently healthy animals. Out of 47 horses which participated in strenuous exercise, three mares showed sudden onset of immobility and reluctance to move and two mares died. Clinical examination revealed that these five horses (group 1) had fever, anorexia, weakness and severe icterus and, in two mares, haemoglobinuria. Haematological examination revealed that all five horses were heavily parasitized with Babesia equi. This was also found in four horses (group 2) with no evidence of clinical babesiosis. In group 3 (94 horses), neither clinical signs nor B. equi were observed in the blood. The horses in group 1 and 2 recovered after treatment with imidocarb. When the mean values of white blood cell count, red blood cell count, haemoglobin and packed cell volume in group 1 were compared with those for groups 2 and 3, a significant difference was found (P < 0.05). A significant difference was also found when the mean values were compared before and after treatment. Examination of serum total protein, bilirubin and serum enzymes revealed a significant decrease in the mean value of total serum protein (P < 0.05), and a significant increase in the mean values of bilirubin (P < 0.05) in group 1 compared to groups 2 and 3. A significant elevation in the mean value of aspartate aminotransaminase, gamma-glutamyltransferase and creatine phosphokinase and a substantial elevation in the mean value of alkaline phosphatase was also observed in group 1 compared to groups 2 and 3. Postmortem examination of the dead horses showed that the animals had icterus, hepatomegaly and full urinary bladder with deep-red urine. Histopathological examination of the liver showed massive centrilobular degeneration and necrosis. The bile canaliculi and bile ducts were prominent and plugged with dark-brown to canary-coloured bile pigments. The lungs had congestion, oedema, and thrombosis of pulmonary veins. Our results suggest that the horses suffered from B. equal with clinical manifestation following exercise. The clinical, haematological and pathological findings indicate that the animals suffered from haemolytic anaemia which responded to imidocarb therapy.

Epidemiology of ovine brucellosis in Awassi sheep in Northern Jordan

We used a combined cross-sectional and longitudinal design to estimate seroprevalence of Brucella antibodies in Awassi sheep and the incidence of abortion due to brucellosis during one lambing season, and to test risk factors. The Brucella organisms isolated from aborted fetuses and vaginal swabs were characterized as Brucella melitensis biotype 3. Seventy Awassi sheep flocks were selected randomly from Northern Jordan. Sixty two of the 70 flocks were used in the cross-sectional study and 8 flocks were monitored for three consecutive months to estimate the incidence of abortion. Questionnaire data and 602 serum samples were collected and analyzed. Thirty five flocks (56%) were brucellosis-seropositive by the Rose Bengal plate-agglutination test (RBT) and 28 (45%) by enzyme-linked immunosorbent assay (ELISA). The crude seroprevalence of brucellosis at the individual-animal level was 14.3% by RBT, 7.2% by ELISA and 2.2% using both tests in series. The flock-specific, animal-level abortion risk ranged between 2.5 and 50% (median=22.6%). The flock brucellosis-status was used as the outcome variable in a multivariable logistic regression. Grazing at communal pasture increased odds, but usage of disinfectants, previous vaccination for brucellosis, and tap water were protective. The animal-level incidence of abortion was 20% and the specific incidence risk of abortion due to brucellosis was 13%.

Epidemiological studies of clinical and subclinical ovine mastitis in Awassi sheep in Northern Jordan.

Forty-six Awassi sheep flocks selected by stratified random sampling were subjected to a cross-sectional study to determine the prevalence of intramammary infections, to assess the influence of flock size and parity on the prevalence of somatic cell count (SCC) and to identify major udder pathogens. Of the 3472 udder halves examined, 29.8% had over 10(6) SCC/ml and 0.03% had dry teats due to chronic mastitis. Flocks with 30-49 milking ewes (small flock size) were much younger (P < 0.001) than flocks with 50-99 ewes (medium) and flocks with > or = 100 ewes (large). Pairwise analysis of the InSCC of both halves of the udders revealed significant mean differences for small and large flock size (P < 0.05), and for medium and large flock size (P < 0.001). Mean InSCC was lower (P < 0.05) in samples obtained from the left half compared with samples of the right half of the udder. Multiparous ewes had higher (P < 0.001) mean InSCC than primiparous ewes. Also, ewes with twin lambs had higher (P < 0.001) mean InSCC in the right half of the udder compared with single-lamb ewes. Samples collected in January (winter) had lower (P < 0.05) mean InSCC compared with samples collected in June. The most common organisms isolated from subclinical mastitis cases were coagulase-negative Staphylococci (17.8%), E. coli (13.6%), Streptococcus agalactiae (6.8%) and Staphylococcus aureus (6.8%). Of the 46 flocks, 20 were monitored monthly for 9 consecutive months to determine the incidence of clinical mastitis diagnosed by shepherds or/and sheep farmers with major pathogens. The incidence of clinical mastitis (expressed as the number of clinical cases per 100 ewe-months) were 2.1 +/- 1.9 (SD), 1.9 +/- 1.1, and 1.2 +/- 2.1 for small, medium and large flocks size strata, respectively. The overall population estimate was 1.7 +/- 0.02 cases per 100 ewe-months. The most-common clinical isolates were S. aureus (22% of all clinical isolates) and E. coli (14.2%).

An explanation of the use of principal-components analysis to detect and correct for multicollinearity

Abstract Multicollinearity can be a serious statistical problem in data analysis in which the contribution of each individual risk factor is being evaluated. Symptoms, effects and techniques that are useful in detecting the presence of multicollinearity in a data base are discussed. The mathematical basis of the principal-components analysis technique for detecting, quantifying, and adjusting the regression coefficients for the effects of multicollinearity in a data base was demonstrated.

Epidemiological and economic study of the repeat breeder syndrome in Michigan dairy cattle. I. Epidemiological modeling

Two models of repeat breeder syndrome (RBS) were developed using data obtained from dairy herds participating in the National Animal Health Monitoring System (NAHMS) in Michigan. These models were designed to study the relationship between RBS and six common risk factors: (1) herd characteristics and environment; (2) nutrition during the dry period; (3) diseases which occurred within 72 h of calving; (4) diseases which occurred more than 72 h after calving; (5) reproductive management; (6) milk production. In Model 1, principal components analysis was used to examine the interrelationships among the risk factors. The variable-synthesis approach was used to combine related risk factors into one common risk factor. Herd characteristics and diseases which occurred within 72 h of calving were significant determinants of RBS (P≤0.01).Milk fever, dystocia and retained placenta occurred as a complex and contributed the most to the cumulative incidence (CI) rate of RBS. In Model 2, a path model was developed to display and to quantify the associations among the significant risk factors that were obtained from Model 1. Dystocia was positively associated with the CI of RBS directly. Milk fever was associated with RBS indirectly through dystocia. Increasing the proportion of corn silage to alfalfa in rations fed to dry cows was associated positively with the CI rate of milk fever and was associated negatively with the CI rate of dystocia. Results of this study suggest that the ration of the dry cow should be balanced in order to prevent dystocia, milk fever and RBS.

Evaluation of Precision Xceed® meter for on-site monitoring of blood β-hydroxybutyric acid and glucose concentrations in dairy sheep

The accuracy of the Precision Xceed® hand-held meter as an on-site method for measuring blood β-hydroxybutyric acid (BHBA) and glucose concentrations, for the diagnosis of pregnancy toxemia and ketosis in dry and lactating dairy sheep, was assessed. Five to eight hours after the start of the morning feed, blood was collected once from 193 clinically healthy sheep (143 dry and 50 lactating). BHBA and glucose analyses were performed with serum in the laboratory, and with whole blood with the Precision Xceed®. Overall, BHBA and glucose determinations by the two methods were not statistically different (P>0.05). Strongly significant positive correlations were found for glucose and BHBA concentrations between the Precision Xceed® and laboratory results (r=0.76, n=150, P<0.01 and r=0.99, n=193, P<0.01, respectively). The Precision Xceed® was highly sensitive (98.6%) and specific (98.2%), and had excellent test agreement for the detection of pregnancy toxemia and ketosis.

Prevalence and pathology of foreign bodies (plastics) in Awassi sheep in Jordan

Abstract The prevalence and associated pathology of foreign bodies in 1453 sheep presented to the Veterinary Clinic during a 27 month period and in the rumen and reticulum from 300 sheep from Amman and Irbid slaughterhouses were studied in Jordan. Of the 1453 sheep, 130 had rumen impaction by plastic and were treated by rumenotomy. The type and location of foreign bodies were examined in 54 out of the 130 sheep. Plastics were the most common (74%), rope and leather were the least common (7%), and all were found in the rumen. Pins and nails were encountered (18.5%) in both rumen and reticulum. Plastic bags were also the most common (78%) foreign bodies found in the rumen of sheep examined in Amman and Irbid from slaughterhouses. In 20 sheep (6.6%), metal masses were found in the rumen. Only in 3 sheep (1%) were pins and nails present in the reticulum. Gross examination of the rumens with plastic revealed areas of sloughing, hemorrhages, congestion and stunting of the papillae. Histopathological examinations revealed areas of coagulative necrosis, hyperemia, inflammatory processes and focal hyperplasia. Several mitotic figures and cells with more than one nucleolus were also present. The results suggest that the plastics in the rumen may play an important role in the pathogenesis of rumenitis. The results, also, suggest that the most common types of foreign bodies in Jordan are plastics and a clean up of the environment would substantially reduce the prevalence of foreign body-pica syndrome in sheep.

Incidence of clinical mastitis and prevalence of subclinical udder infections in Jordanian dairy cattle

Abstract Nineteen Jordanian dairy farms selected by stratified random sample were monitored between July 1991 and August 1992 in order to: (a) determine the incidence of clinical mastitis; (b) assess the influence of season and herd size on the incidence of clinical mastitis; (c)_estimate and identify major udder pathogens and their prevalence. Sixty-five percent of clinical mastitis cases occured between December and April. The incidence of clinical mastitis was 6.8, 5.0 and 3.3 cases per 100 cow-months at risk for herds with 10–29 cows, 30–59 cows, and more than 59 cows, respectively. The most common organisms isolated from clinical cases were coagulase-negative staphylococci (16%) and Staphylococcus aureus (14%). The most prevalent bacterial pathogens in subclinical udder infections were coagulase-negative staphylococci (9.4–11.8%), Staphylococcus aureus (9.2–12.1%) and Corynebacterium bovis (5.8–7.5%). The prevalence rates of Escherichia coli and Enterobacter spp. increased during the winter season for the three herd-size strata.

Ovine and caprine brucellosis (Brucella melitensis) in aborted animals in Jordanian sheep and goat flocks.

Two hundred and fifty five biological samples were collected from 188 animals (81 sheep and 107 goats) during the lambing season from September 2009 to April 2010 from the Mafraq region of Jordan. Sampled animals belonged to 93 sheep and goat flocks that had abortion cases in the region. One hundred and seven (41.9%) biological samples were positive for the omp2 primers that were able to identify all Brucella species in the collected samples which were obtained from 86 aborted animals (86/188 = 45.7%). Using the B. melitensis insertion sequence 711 (IS711) primers on the 107 omp2 positive samples, only 61 confirmed to be positive for B. melitensis. These positive samples were obtained from 28 sheep and 33 goats. The prevalence rate of B. melitensis was 27.1% (51/188) among aborted animals. For differentiation between vaccine strain and field strain infection, polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method using PstI endonuclease enzyme was used. Vaccination with Rev-1 in the last year (OR = 2.92, CI: 1.1–7.7) and grazing at common pasture (OR = 2.78, CI: 1.05–7.36) were statistically significant (P ≤ .05) risk factors positively associated with the occurrence of brucellosis in sheep and goat flocks.

Ovine and caprine toxoplasmosis ( Toxoplasma gondii ) in aborted animals in Jordanian goat and sheep flocks

Two hundred and fifty-five biological samples (106 aborted foetal tissue samples and 149 blood samples from aborted sheep and goats) were collected from 188 animals during the lambing season from September 2009 to April 2010 from the Mafraq region of Jordan. The sampled animals belonged to 93 goat and sheep flocks that had cases of abortion. A total of 169 (66.3%) biological samples were collected from sheep and 86 (33.7%) from goats. Seventy-six (29.8%) biological samples (45 blood and 31 tissue samples) were positive for Toxoplasma gondii by PCR assay. The positive samples were obtained from 43 sheep and 23 goats. The overall toxoplasma-specific prevalence rate was 35.1% (66/188). Forty flocks (43%) had at least one T. gondii PCR-positive animal. The risk factors related to flock health status and farm management that are hypothesized to be associated with T. gondii PCR positivity were also assessed using multiple logistic regressions. The presence of cats (OR = 4.74), a large flock size (OR = 2.76) and the method of disposing the aborted foetuses (OR = 3.77) were all statistically significant (P < 0.05) risk factors that were positively associated with toxoplasma positivity in goat and sheep flocks.