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ABSTRACT: A cross-sectional sero-survey, using a two-stage cluster sampling design, was conducted between 2002 and 2003 in ten administrative regions of central and southern Somalia, to estimate the seroprevalence and geographic distribution of rinderpest (RP) in the study area, as well as to identify potential risk factors for the observed seroprevalence distribution. The study was also used to test the feasibility of the spatially integrated investigation technique in nomadic and semi-nomadic pastoral systems. In the absence of a systematic list of livestock holdings, the primary sampling units were selected by generating random map coordinates. A total of 9,216 serum samples were collected from cattle aged 12 to 36 months at 562 sampling sites. Two apparent clusters of RP seroprevalence were detected. Four potential risk factors associated with the observed seroprevalence were identified: the mobility of cattle herds, the cattle population density, the proximity of cattle herds to cattle trade routes and cattle herd size. Risk maps were then generated to assist in designing more targeted surveillance strategies. The observed seroprevalence in these areas declined over time. In subsequent years, similar seroprevalence studies in neighbouring areas of Kenya and Ethiopia also showed a very low seroprevalence of RP or the absence of antibodies against RP. The progressive decline in RP antibody prevalence is consistent with virus extinction. Verification of freedom from RP infection in the Somali ecosystem is currently in progress.
Revue scientifique et technique (International Office of Epizootics) 12/2010; 29(3):497-511. · 1.10 Impact Factor
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ABSTRACT: The objective of this study was to evaluate the use of a one-tube nested polymerase chain reaction (OTN PCR) with 5 concentration and lytic treatments for the detection of Mycobacterium bovis in experimentally inoculated milk samples (spiked samples). OTN PCR and the following treatments were tested in inoculated samples: 1) centrifugation; 2) C18-carboxypropylbetaine + capture resin 1 + Proteinase K (CB18-CH-PK); 3) centrifugation + capture resin 1 + Proteinase K; 4) centrifugation + capture resin 2 + Proteinase K; and 5) centrifugation + immunomagnetic separation (IMS). The OTN PCR and the 5 treatments were evaluated in 2 different sets of spiked milk samples. One set consisted of 10-fold serial dilutions of a phenol-killed M. bovis in milk to final concentrations ranging from 5 to 50,000 cells/ml of milk. The other set of samples consisted of 2.5 serial dilutions of milk spiked with M. bovis to final concentrations ranging from 20.5 to 5,000 cells/ml of milk. Each treatment was repeated 5 times at each cell concentration. CB18-CH-PK and IMS were significantly more sensitive than other treatments. The lowest detection limit for these techniques was 20-50 cells/ ml of spiked milk. The specificity of OTN PCR in this study was high as demonstrated by the lack of DNA amplification products when M. bovis cells were not present in the samples. [The OTN PCR used in conjunction with CB18-CH-PK or IMS could be effectively used as a diagnostic and/or screening test for the detection of M. bovis in milk from herds with bovine tuberculosis.]
Journal of veterinary diagnostic investigation: official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc 04/2001; 13(2):111-6. · 1.21 Impact Factor
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ABSTRACT: LH* is a scalable distributed data structure that extends linear hashing to support file manipulations in a distributed environment. The purpose of the paper is to investigate the behavior of concurrent transactions in the context of LH*. We present an algorithm to synchronize concurrent transactions in LH*. The algorithm exploits the semantics of LH* and verifies the valves of the addressing parameters during two consecutive reads to detect any harmful interference. After an operation completes its manipulation, it still holds the key lock till the transaction commits or aborts. However, to simply move the lock information along with the relocated keys cannot ensure correctness during a split. A locking protocol is therefore proposed to solve the inconsistency. Furthermore, a causal relationship is formed by associating a timestamp with each range query to eliminate the necessity of atomic broadcast
Database and Expert Systems Applications, 1996. Proceedings., Seventh International Workshop on; 10/1996
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ABSTRACT: Fecal samples from 7,369 calves on 1,103 farms were examined for cryptosporidia in a nationwide survey, using monoclonal antibody technique. Cryptosporidium oocysts were found in calves from 652 (59.1%) of the farms and in 1,648 (22.4%) of the tested calves. Almost half the calves between 7 and 21 days of age had cryptosporidia in their fecal samples. Prevalence was highest during the summer. Farms with multiple-cow maternity facilities and farms with > 100 milking cows were the most likely to have calves with cryptosporidia.
Journal of the American Veterinary Medical Association 07/1994; 205(1):86-91. · 1.79 Impact Factor
