Subclinical mastitis in dairy cattle and buffaloes among small holders in Egypt: Prevalence and evidence of virulence of Escherichia coli causative agent.

This study aimed first to estimate the prevalence of subclinical mastitis (SCM) among dairy cows and buffaloes of smallholders who sell milk directly to consumers through bulk tanks of milk distributors. The second aim is to estimate the prevalence of Escherichia coli in milk of SCM cases and identify its virulence genes and to emphasize the public health risk form drinking this milk. A total of 227 and 174 dairy cows and buffaloes, respectively from Kafrelsheikh Governorate, Egypt were examined with California Mastitis Test (CMT) to estimate the prevalence of SCM. Samples were also screened for E. coli using classical bacteriological and molecular methods. The prevalence of CMT-positive cows and buffaloes samples examined was 47.4% (49.9% and 44.3% for cows and buffaloes, respectively). Cows were found to be at a higher risk of getting high CMT score than buffaloes. E. coli was detected bacteriologically in 16.4% and in 27.2% of the CMT-positive cows and buffalo samples, respectively. A total of 83.1% and 75.6% of isolates were confirmed as E. coli using PCR technique. A multiplex PCR assay was used to identify five virulence genes in the E. coli isolates; the eae gene for enteropathogenic E. coli, stx for Shiga toxin-producing E. coli, elt and est for enterotoxigenic E. coli, and the hlyA of the enterohemolysin gene for enterohemorrhagic E. coli. Only one E. coli strain identified carried two virulence genes (eae and est). The high prevalence of SCM among dairy cows and buffaloes in the study area indicated that there is high risk to consumers who consume milk of these animals. Also, control of SCM is a prerequisite among smallholders in Egypt in order to minimize its deleterious effects such as microbial antibiotic resistance and public health hazards. To our knowledge, this is the first study that highlights the ecology of virulence by E. coli causing SCM in Kafrelsheikh governorate, Egypt. This study offers the basis for further phenotypic and molecular characterization of E. coli found in raw milk in order to guarantee safe consumption of raw milk and milk products.

Temporal Analysis and Costs of Ruminant Brucellosis Control Programme in Egypt Between 1999 and 2011.

Data for the prevalence of brucellosis in ruminants in Egypt are scarce; recent studies suggest the disease is endemic, with a high prevalence. The aim of this study was to assess the financial costs and the impact of the current control programme on the pattern of brucellosis among ruminants between 1999 and 2011. A univariate binary logistic regression model was used to compare between seropositive proportions for different years for each species. The proportion of seropositive cattle was significantly increased from 2000 to 2004 then significantly decreased from 2005 to 2011. The proportion of seropositive buffalo fluctuated year to year; however, there was a significant increase in 2008 (OR 3.13, 95% CI 2.69-3.66, P < 0.001). There was a decrease in the proportion of seropositive sheep during the study period except in 2001 and 2009 in which there was a significant increase. The proportion of seropositive goats increased in 2000 and 2001, and then decreased from 2002 to 2007. In 2008, there was a significant increase in the seropositive proportion of goats (OR 2.53, 95% CI 2.21-2.90, P < 0.001). The average annual cost for the control programme including testing and compensation was more than US$3 million. The total cost for the control programme including testing and compensation for the period (13 years) between 1999 and 2011 was more than US$40 million, from which more than 56% for cattle. Further studies are required for the effectiveness of the current control strategies and alternative strategies should be considered. The socio-economic impact of brucellosis and its control measures should be investigated.

Systematic review of brucellosis in the Middle East: disease frequency in ruminants and humans and risk factors for human infection.

A systematic review of studies providing frequency estimates of brucellosis in humans and ruminants and risk factors for Brucella spp. seropositivity in humans in the Middle East was conducted to collate current knowledge of brucellosis in this region. Eight databases were searched for peer-reviewed original Arabic, English, French and Persian journal articles; the search was conducted on June 2014. Two reviewers evaluated articles for inclusion based on pre-defined criteria. Of 451 research articles, only 87 articles passed the screening process and provided bacteriological and serological evidence for brucellosis in all Middle Eastern countries. Brucella melitensis and B. abortus have been identified in most countries in the Middle East, supporting the notion of widespread presence of Brucella spp. especially B. melitensis across the region. Of the 87 articles, 49 were used to provide evidence of the presence of Brucella spp. but only 11 provided new knowledge on the frequency of brucellosis in humans and ruminants or on human risk factors for seropositivity and were deemed of sufficient quality. Small ruminant populations in the region show seroprevalence values that are among the highest worldwide. Human cases are likely to arise from subpopulations occupationally exposed to ruminants or from the consumption of unpasteurized dairy products. The Middle East is in need of well-designed observational studies that could generate reliable frequency estimates needed to assess the burden of disease and to inform disease control policies.

Caseous lymphadenitis in small ruminants in Egypt. Clinical, epidemiological and prophylactic aspects.

OBJECTIVE: The aim of this study was to investigate the distribution of caseous lymphadenitis (CLA) among small ruminants in Egypt, identify risk factors associated with its occurrence and to analyze the efficacy of the vaccine for control of CLA. MATERIAL AND METHODS: A total of 1206 sheep and 351 goats were examined clinically for CLA. The prevalence and the risk factors of CLA in small ruminant flocks were estimated and identified. Efficacy of the commercial vaccine Case-Bac (Colorado Serum Company, USA) was determined in a field study trial conducted on 15 CLA-free lambs. Follow-up of vaccination immune response was carried out using indirect ELISA. RESULTS: Prevalence of superficial CLA was 6.7%. Clinically, CLA appeared as abscesses in superficial lymph nodes mostly of the head and neck. On the basis of a multivariate analysis which accounted for clustering at herd level, sheep were at risk of getting superficial CLA 3.5 times more than goats (p < 0.0001). Animals of fixed flocks were at risk of getting the superficial CLA 2 times more than animals in fixed-mobile flocks (p < 0.038). Serological follow-up indicated protective antibody titers for 6 months. In vaccinated animals clinical cases were not observed while they occurred among non-vaccinated sheep. DISCUSSION: Prevalence of CLA varied among studied flocks even between those of the same breeding system due to complex and overlapping factors associated with each flock like introduction or culling rate of animals, care of shepherds or owners to deal with opened abscesses in addition to the average age of the animals within each flock. Breeding systems have observable effects on occurrence of CLA: infected sheep can transmit the infection to a large number of animals in a short period under the conditions of close contact and reduced air flow in covered sheds. CONCLUSION AND CLINICAL RELEVANCE: Infected small ruminants in fixed flocks represent a risk factor for CLA for healthy ones. The vaccine used in the study provides an effective protection against new infections. So mass vaccination of small ruminants against CLA in Egypt has to be considered to minimize the disease prevalence.

Ruminant brucellosis in Upper Egypt (2005-2008).

Brucellosis is endemic among humans and ruminant in Egypt and recent reports suggest that its incidence may be increasing. In this study we describe the frequency of brucellosis among different ruminant species in Upper Egypt and its spatial distribution using the data generated by a large-scale control campaign undertaken between 2005 and 2008. A total of 120,090 individual animals of different ruminant species were tested during the campaign. The true proportions of brucellosis were estimated as 0.79% (CI: 0.71%-0.87%), 0.13% (CI: 0.08%-0.18%), 1.16% (1.05%-1.27%) and 0.44% (0.34%-0.54%) among cattle, buffaloes, sheep and goats respectively. We estimated that 0.2% (CI: 0.16%-0.23%) of households in the study area keep at least one seropositive animal. Spatial autocorrelation of the proportions of seropositive households and seropositive animals was assessed using Global Univariate Moran's I and Local Univariate LISA. These analyses showed that the distribution of seropositive animals has considerable spatial heterogeneity with clustering in the northern governorates of the study area. Our results show that brucellosis is widespread and heterogeneously distributed in Upper Egypt. At the current level of available resources it is very unlikely that test and slaughter could be implemented with the intensity needed to be effective and other control measures that could replace or complement the test and slaughter policy in place should be considered. Also, this study illustrates some of the challenges faced by bilateral projects that have to accommodate an externally funded intervention with an ongoing national official disease control program.

Assessment and simulation of the implementation of brucellosis control programme in an endemic area of the Middle East.

Brucellosis is an important zoonosis in Middle Eastern countries. In this study we assessed the extent of the application of planned official brucellosis control programmes in Kafr El Sheikh governorate, Egypt and we used a stochastic simulation model to assess the probable impact of changes to the official control strategy on the dynamics of small-ruminant brucellosis. Our results show that <7% of female livestock were tested in any given year in the study area and that quarantine was not consistently applied to infected herds. Simulation results revealed the inability of the applied control measures to reduce the prevalence of small-ruminant brucellosis. Given our assumptions, the intensity with which infected animals are removed under the actual levels of implementation of test-and-slaughter programmes would permit brucellosis to remain endemic at a level >8% of the sheep and goat population.