Eyal Klement

Mathematical modelling and evaluation of the different routes of transmission of lumpy skin disease virus

Lumpy skin disease (LSD) is a severe viral disease of cattle. Circumstantial evidence suggests that the virus is transmitted mechanically by blood-feeding arthropods. We compared the importance of transmission via direct and indirect contact in field conditions by using mathematical tools. We analyzed a dataset collected during the LSD outbreak in 2006 in a large dairy herd, which included ten separated cattle groups. Outbreak dynamics and risk factors for LSD were assessed by a transmission model. Transmission by three contact modes was modelled; indirect contact between the groups within a herd, direct contact or contact via common drinking water within the groups and transmission by contact during milking procedure. Indirect transmission was the only parameter that could solely explain the entire outbreak dynamics and was estimated to have an overall effect that was over 5 times larger than all other possible routes of transmission, combined. The R0 value induced by indirect transmission per the presence of an infectious cow for 1 day in the herd was 15.7, while the R0 induced by direct transmission was 0.36. Sensitivity analysis showed that this result is robust to a wide range of assumptions regarding mean and standard deviation of incubation period and regarding the existence of sub-clinically infected cattle. These results indicate that LSD virus spread within the affected herd could hardly be attributed to direct contact between cattle or contact through the milking procedure. It is therefore concluded that transmission mostly occurs by indirect contact, probably by flying, blood-sucking insects. This has important implications for control of LSD.

Canine monocytic ehrlichiosis: a retrospective study of 100 cases, and an epidemiological investigation of prognostic indicators for the disease

One hundred cases of monocytic ehrlichiosis diagnosed in Israeli dogs were confirmed by the presence of anti-Ehrlichia canis indirect immunofluorescent antibody titres greater than 1:40. The disease occurred in all age groups and there was no sex predilection. German shepherd dogs were significantly over-represented whereas crossbreed dogs were significantly under-represented (P>0.0005). The most common clinical signs were depression, lethargy, lymphadenomegaly, fever, anorexia, panting, pale mucous membranes and bleeding, of which epistaxis was most common. Thrombocytopenia, anaemia (mainly normocytic normochromic) and lymphopenia were the predominant haematological findings. Forty-nine of the 100 cases were followed up for a year. Thirty-two dogs survived and 17 died. A Cox proportional hazards regression model was used to examine the effect of host, environmental, and haematological prognostic factors on survival. It was concluded that severe anaemia, severe leucopenia, pancytopenia, a tendency to bleed (especially epistaxis) and being a German shepherd dog were important indicators of poor survival in cases of monocytic ehrlichiosis in dogs.

Heat Stroke in Dogs: A Retrospective Study of 54 Cases (1999–2004) and Analysis of Risk Factors for Death

The medical records of 54 dogs presented to the Hebrew University Veterinary Teaching Hospital and diagnosed with heat stroke were retrospectively reviewed. Data abstracted included history, clinical and clinicopathological signs at admission, treatment, disease progression, and outcome. Exertional and environmental heat stroke were present in 63% (34 of 54) and 37% (20 of 54) of the dogs, respectively, and 78% (42 of 54) were examined between June and August. The mean temperature and heat discomfort index in the particular days of heat stroke were significantly increased (P < .001, P < .001, respectively) compared with their corresponding average daily values. In 27 dogs the body temperature was > or = 41 degrees C (105.8 degrees F). Belgian Malinois (15%, odds ratio [OR] = 24, 95% confidence interval [CI95%] 8.2-64.5), Golden and Labrador Retrievers (21%, OR = 2.08, CI95% 0.95-4.2), and brachycephalic breeds (25%, OR = 1.7, CI95%], 0.81-3.21) were overrepresented, whereas small breeds (<8 kg) were underrepresented (2%, OR = 0.08, CI95%, 0.002-0.48). Thrombocytopenia (45 of 54 dogs) and prolongation of the prothrombin (PT) and activated thromboplastin (aPTT) times (27 of 47 dogs) were recorded during hospitalization. Disseminated intravascular coagulation (P = .013) and acute renal failure (P = .008), diagnosed in 28 of 54 and 18 of 54 of the cases, respectively, were risk factors for death. The overall mortality rate was 50%. Hypoglycemia (<47 mg/dL, P = .003), prolonged PT (>18 seconds, P = .05), and aPTT (>30 sec, P < .001) at admission were associated with death. Serum creatinine >1.5 mg/dL (P = .003) after 24 hours, delayed admission (>90 minutes, P = .032), seizures (P = .02), and obesity (P = .04) were also risk factors for death. Heat stroke in dogs results in serious complications and high fatality rate despite appropriate treatment.

Childhood hygiene is associated with the risk for inflammatory bowel disease: a population-based study.

OBJECTIVES:The “hygiene hypothesis” postulates that individuals raised in a sanitary environment are more likely to develop inflammatory bowel disease (IBD). Several studies previously demonstrated contradictory results in this regard. We performed for the first time a population-based study on the association of surrogate markers of childhood hygiene with the risk for IBD.METHODS:A cross-sectional population-based study was undertaken. Information on number of siblings, birth order, and living in an urban versus rural environment was obtained for 399,251 Jewish adolescents at the age of 17 yr from 1998 to 2004. The study population included only subjects born in Israel. In order to control for genetic confounding, subjects were also divided according to their ethnic group as being Ashkenazi, Sephardic, or Israeli in origin.RESULTS:In total, 768 cases of inflammatory bowel disease (IBD) were diagnosed (0.19%), with 53.8% of the cases being of Ashkenazi origin. On multivariate analysis, variables significantly associated with IBD were male gender (odds ratio [OR] 1.44, 95% confidence interval [CI] 1.24–1.67), Ashkenazi origin (OR 1.91, 95% CI 1.63–2.22), living in an urban environment (OR 1.38, 95% CI 1.02–1.78), small number of siblings in the family (for 1 sibling vs 5 or more, OR 2.63, 95% CI 1.49–4.62), and higher birth order (for birth order of 5 or higher vs 1, OR 2.35, 95% CI 1.47–3.77), showing for both variables an almost strictly highly significant monotonic association (P value for trend <0.001).CONCLUSIONS:Surrogate markers of childhood hygiene are associated with the risk for IBD, thus reinforcing the “hygiene hypothesis.”

Retrospective study of 46 cases of feline haemobartonellosis in Israel and their relationships with FeLV and FIV infections

Forty-six cats with clinical haemobartonellosis were studied; 75 per cent of the cats of known age were two-and-a-half years old or younger, 50 per cent were intact males and 19.5 per cent were castrated males. The predominant signs of the disease were tachypnoea, lethargy, depression, anorexia, infestation with fleas, pale mucous membranes, icterus, emaciation, dehydration, splenomegaly, anaemia, leucocytosis, increased activities of alanine aminotransferase and aspartate aminotransferase, and azotaemia. Thirty-eight per cent of the cats that were tested for feline leukaemia virus (FeLV) antigen were positive, and 22 per cent of those tested for feline immunodeficiency virus (FIV) antibodies were positive. The prevalence of both FeLV and FIV was much higher than in the general Israeli cat population. The cats infected with both Haemobartonella felis and FeLV had a significantly lower body temperature, were more anaemic and the mean cell volume of their erythrocytes was greater than in the cats with haemobartonellosis alone.

Identification of Risk Factors for Infection in an Outbreak of Mycoplasma pneumoniae Respiratory Tract Disease

BACKGROUND Mycoplasma pneumoniae is one of the most common pathogens that causes community-acquired respiratory tract infection. Outbreaks are well known, and all age groups are susceptible. An outbreak in an army training unit afforded an opportunity to identify possible risk factors for morbidity. METHODS An outbreak of respiratory illness that occurred in a unit comprising 91 trainees was investigated and analyzed as a cohort study. M. pneumoniae infection was suspected on clinical grounds and was confirmed by polymerase chain reaction, culture, and serologic testing. Data regarding medical history, symptoms, signs, and laboratory tests were collected. RESULTS During a period of 12 days, 41 soldiers (45.1%) had respiratory illnesses, of which 10 (11.0%) were pneumonia. Comparison of symptomatic and asymptomatic individuals revealed that smoking was associated with higher rates of disease (risk ratio, 2.1; 95% confidence interval [CI], 1.3-3.2; P<.005) and seroconversion (risk ratio, 2; 95% CI, 1.2-3.4; P=.03). In multivariate analysis, both lower acute immunoglobulin G values (adjusted odds ratio, 7.8; 95% CI, 1.4-42.5; P=.018) and smoking (adjusted odds ratio, 5.6; 95% CI, 1.5-20.4; P=.01) were associated with symptomatic infection; stratification according to smoking status revealed that immunoglobulin G levels among nonsmokers were protective. Patients who had pneumonia had lower lymphocyte counts (1400+/-258 vs. 2000+/-465 cells/microL; P=.001). CONCLUSIONS Smoking and lower preexisting immunoglobulin G levels were strongly associated with M. pneumoniae respiratory infection. These findings emphasize the importance of immunity and cessation of smoking for the prevention of disease. The high attack rate emphasizes the extent of infection transmission among healthy persons living in close contact.

Assessment of the productivity effects associated with epizootic hemorrhagic disease in dairy herds.

Epizootic hemorrhagic disease is caused by a Culicoides-borne Orbivirus. In cattle, the disease is characterized by reduced milk production and mortality. Recent outbreaks of epizootic hemorrhagic disease virus (EHDV) in North Africa, Israel, and Turkey increase the risk of its invasion into central and northern Europe. An outbreak of EHDV in Israel during the fall of 2006 enabled an assessment of the consequent production losses to the dairy cattle industry. Reduction in milk production and involuntary culling were modeled using a 4-yr database of monthly milk and mortality records from 48 affected and 63 unaffected herds. These indices were compared between periods of outbreak and no outbreak and assessed for various levels and exposure onset. Geospatial kriging interpolation of serological results from 127 herds was used to assess the total outbreak losses for the dairy cattle industry in Israel. Herds affected during the first, second, and third month of the outbreak (September-November) experienced an average loss of 207 (95% CI=154-261), 137 (63-211), and 52 (27-76) kg of milk/milking cow, respectively, during the outbreak period. An average excess mortality and involuntary culling of 1.47/100 cows was documented in herds affected in September. High correlation was observed between EHDV seroprevalence and milk loss; average milk loss for herds with seropositivity of 26 to 50, 51 to 75, and 76 to 100% was 84, 133, and 204 kg of milk/milking cow, respectively. A 1.42% (0.91-1.93%) increase in mortality was observed in herds with seroprevalence above 50%. Losses for the dairy cattle industry interpolated from these data were estimated at US

Clinical and Immune Responses after Revaccination of Israeli Adults with the Lister Strain of Vaccinia Virus

2,491,000 (US

Prognostic indicators for canine monocytic ehrlichiosis

1,591,000-3,391,000), an average loss of US

No Association between Histo—Blood Group Antigens and Susceptibility to Clinical Infections with Genogroup II Norovirus

26.5/cow in the Israeli dairy cattle. This equals 0.55% of the average total value production of a dairy cow in Israel. This is the first study to estimate the production losses caused by EHDV or any bluetongue-like disease.