Determination of the wax ester content in olive oils. Improvement in the method proposed by EEC regulation 183/93

A simpler and faster procedure than the official one described in document IV of European Economic Community Regulation 183/93 is proposed. The wax ester fraction is isolated from triglycerides using a commercially available silica gel column and carbon tetrachloride as eluent. The recovered wax ester fraction, with the addition of a suitable internal standard solution, is analyzed by gas chromatography. A column with a 65% phenyl methyl silicone stationary phase allows a satisfying separation of wax ester fraction in comparison with both a steryl ester and a light fraction eluted before the internal standard. Furthermore, also the single components of the wax ester fraction are suitably separated.     

Brucellosis among smallholder cattle farmers in Zambia

A cross-sectional study was performed in Southern and Lusaka provinces of Zambia between March and September 2008 to estimate Brucella seroprevalence in cattle kept by smallholder dairy farmers (n = 185). Rose Bengal test (RBT) was used as a screening test followed by confirmation with competitive ELISA (c-ELISA). We investigated 1,323 cattle, of which 383 had a history of receiving vaccination against brucellosis and 36 had a history of abortion. Overall seroprevalence was 6.0% with areas where vaccination was practiced having low seroprevalence. Age was associated with Brucella seropositivity (P = 0.03) unlike cattle breed (P = 0.21) and sex (P = 0.32). At area level, there was a negative correlation (Corr. coeff = −0.74) between percentage of animals with brucellosis vaccination history (vaccination coverage) and level of brucellosis; percentage of animals with history of abortion (Corr. coeff. = −0.82) and brucellosis vaccination coverage. However, a positive correlation existed between brucellosis infection levels with percentage of animals having a history of abortion (Corr. coeff. = 0.72). History of vaccination against brucellosis was positively associated with a positive Brucella result on RBT (P = 0.004) whereby animals with history of vaccination against brucellosis were more likely to give a positive RBT test results (OR = 1.52). However, the results of c-ELISA were independent of history of Brucella vaccination (P = 0.149) but was positively associated with history of abortion (OR = 4.12). Our results indicate a relatively low Brucella seroprevalence in cattle from smallholder dairy farmers and that vaccination was effective in reducing cases of Brucella infections and Brucella-related abortions. Human exposure to Brucella through milk from smallholder farmers could result through milk traded on the informal market since that milk is not processed and there no quality and safety controls.     

Effectiveness of Rose Bengal test and fluorescence polarization assay in the diagnosis of <Emphasis Type="Italic">Brucella</Emphasis> spp. infections in free range cattle reared in endemic areas in Zambia

The effectiveness of Rose Bengal test (RBT) and fluorescence polarization assay (FPA) in diagnosing cattle brucellosis in endemic areas was assessed and RBT and FPA test agreement was compared (n = 319). The sensitivity of RBT and FPA in detecting low Brucella titres were evaluated in paired sera (n = 34). A logistic regression model was constructed to predict cattle test result in FPA using RBT as the main predictor and incorporating bio-data and animal history. There was 79.3% agreement between the RBT and FPA (Kappa = 0.59; Std error = 0.05; p = 0.000) and a high correspondence between high RBT scores and positive FPA results suggesting that sera with high RBT score may not require confirmation with tests such as competitive-ELISA or CFT. High FPA cut-off points were more likely to miss animals with low antibody titres. The RBT had a reduced ability in detecting low antibody titres compared to the FPA. FPA test interpretation was improved if a priori information, such as sex and age was used. Under the challenging disease surveillance conditions prevailing in rural Africa, field-testing methods that are sensitive and specific; allow single animal contact, low technical skills in data interpretation are suitable.     

Practices of traditional beef farmers in their production and marketing of cattle in Zambia

Understanding the practices of traditional cattle farmers in developing countries is an important factor in the development of appropriate, pro-poor disease control policies, and in formulating regional-specific production incentives that can improve productivity. This paper describes the production, husbandry practices, economics, and constraints of traditional cattle farming in Zambia. A cross-sectional study design was used to obtain data from traditional cattle farmers (n = 699) using a structured questionnaire. Data analyses were carried out using SPSS and STATA statistical packages. The results revealed that the majority [65% (95% CI: 59.3–71.1)] of farmers practised a transhumant cattle herding system under communal grazing. In these transhumant herding systems, animal husbandry and management systems were found to be of poor quality, in terms of supplementary feeding, vaccination coverage, deworming, uptake of veterinary services, usage of artificial insemination, and dip tanks all being low or absent. East Coast Fever was the most common disease, affecting 60% (95% CI: 56.4–63.7) of farmers. Cattle sales were low, as farmers only sold a median of two cattle per household per year. Crop farming was found to be the main source of farm income (47%) in agro-pastoralist communities, followed by cattle farming (28%) and other sources (25%). The median cost of production in the surveyed provinces was reported at US$316, while that of revenue from cattle and cattle products sales was estimated at US$885 per herd per year. This translates to an estimated gross margin of US$569, representing 64.3% of revenue.There is considerable diversity in disease distribution, animal husbandry practices, economics, and challenges in traditional cattle production in different locations of Zambia. Therefore, to improve the productivity of the traditional cattle sub-sector, policy makers and stakeholders in the beef value chain must develop fit-for-purpose policies and interventions that consider these variations.     

Brucella seroprevalence of the Kafue lechwe (Kobus leche kafuensis) and Black lechwe (Kobus leche smithemani): exposure associated to contact with cattle

We investigated Brucella seroprevalence in Kafue (Kobus leche kafuensis) and Black (Kobus leche smithemani) lechwe antelopes to assess Brucella infections in relation to presence/absence of cattle interaction on the wetlands. Accordingly, two study populations based on cattle interaction were assesed: Kafue lechwe from Kafue flats which interact with cattle; and the Black lechwe with no known interaction with cattle from the Bangweulu swamps. Fourteen Kafue lechwe and thirty Black lechwe were slaughtered between October and December 2009 using special research licenses obtained from the Zambia wildlife authority to investigate diseases in lechwe antelope. For the purpose of this study, blood was collected and sera separated for Rose Bengal and indirect ELISA tests. Seroprevalence of Brucella in the Kafue lechwe was estimated at 42.9% [95% CI: 15.2-70.5] while that in Black lechwe was 0% [95% CI:0.0-11.6]. On the Kafue flats, cattle were spotted grazing in the same areas as lechwe while there was no evidence of cattle presence on the Bangweulu swamps. These differences in seroprevalence between Kafue lechwe and Black lechwe were assumed to be associated with interaction between Kafue lechwe and Brucella infected cattle, and no such contact existed between cattle and the Black lechwe. Our study suggests that brucellosis in the Kafue lechwe may have originated from cattle but has now established a reservoir in wild animals. It is also important to keep in mind that the Black lechwe can easily become infected with Brucella spp. once cattle are introduced in the surrounding areas.     

The effect of seasonal variation on anthrax epidemiology in the upper Zambezi floodplain of western Zambia

Anthrax has become endemic throughout the upper Zambezi floodplain located in the Western Province of Zambia over the recent years. To date, no comprehensive study has been carried out to determine whether recurrence of anthrax outbreaks may be linked to differences in precipitation and human activities. Retrospective data for the period 1999 to 2007 showed that a total of 1,216 bovine cases of anthrax were reported. During the same period, 1,790 human anthrax cases and a corresponding case fatality rate of 4.63% (83/1,790) was documented in the upper Zambezi floodplain. Occurrence of human cases was highly correlated with cattle outbreaks (r = 0.94, p < 0.001). Differences in precipitation were significantly associated with the occurrence of anthrax outbreaks (χ² = 4.75, p < 0.03), indicating that the likelihood of outbreaks occurring was higher during the dry months when human occupancy of the floodplain was greater compared to the flooding months when people and livestock moved out of this region. Human dependency on the floodplain was shown to significantly influence the epidemiology of anthrax in the upper Zambezi floodplain of western Zambia. Methods for mitigating anthrax outbreaks by disrupting the cycle of transmission are herein highlighted.     

Mortality and commercial off-take rates in adult traditional cattle of Zambia

A cohort study was conducted in the livestock-wildlife interface areas of Zambia to determine cattle mortality and commercial off-take rates among adult cattle as well as factors influencing them. A total of 416 animals from 43 herds were followed up for one year and animals were individually identified and their fate was indicated as sold, slaughtered, dead or present as appropriate. The overall mortality incidence risk was estimated at 7.5%. Cattle in Kazungula were at a greater risk of dying compared to those in Blue Lagoon and Lochnivar. Annual off-take was estimated at 13.7% (8.1–19.3%), unadjusted values, and 16.4% (8.1–24.5%) after adjusting for sampling fraction in primary sampling units (herds) and area stratification. Area variations were observed with Kazungula recording the highest in both instances, which was attributed to a contagious bovine pleural pneumonia (CBPP) outbreak. Herd size and gender were observed to influence cattle mortality rates. Cattle in the middle-sized herds (50–150 cattle) recorded high mortality rates (OR = 3.91) compared to smaller herds (10–50) and so were females compared to males (OR = 4.16). The logistic regression model showed that cattle death was influenced by managerial factors and that off-take rates tend to increase in the face of disease outbreaks.     

In vitro and in vivo immune stimulating effects of a new standardized Echinacea angustifolia root extract (Polinacea)

Polinacea is a new standardized hydroethanolic extract obtained from Echinacea angustifolia roots containing echinacoside (>4%), the high molecular weight polysaccharide IDN 5405 (>5%) and a isobutylamide fraction (<0.1%). For in vitro tests, a bacterial lipopolysaccharide-free (LPS-free) Polinacea has been prepared in order to avoid non-specific responses of immunocompetent cells. LPS-free Polinacea enhanced the immune functions as highlighted by the proliferation rate and gamma-interferon production in murine T-lymphocyte cell cultures stimulated by anti-CD3. LPS-free Polinacea did not have a direct role on macrophage response as measured in the nitric oxide production test using the J774 macrophage cells line. In vivo, Polinacea showed an immune stimulating activity by reducing the Candida albicans induced mortality both in normal and in cyclosporin A-treated mice.     

Risk factors for brucellosis in indigenous cattle reared in livestock-wildlife interface areas of Zambia

Transmission of Mycobacterium avium subsp. paratuberculosis (Map) to susceptible animals is primarily considered to occur via faeces and milk originating from infectious cows. However, studies of factors resulting in increased transmission of Map are difficult to perform due to a long and unpredictable incubation period and inaccurate diagnostic tests. A multi-level Bayesian mixture model has been shown to predict the infection status of an individual cow more precisely than traditional cut-off based methods used for interpretation of diagnostic test-information, thereby increasing the precision of the diagnostic information.

The objective of our study was to assess management-related risk factors for within-herd transmission of Map. Management-related risk factors were recorded in 97 Danish dairy herds. Twenty-six months following that recording, the antibody status of all lactating cows (n = 7410) in the same herds was measured by the use of an ELISA. A multi-level Bayesian mixture model was used to assess the association between the probability of infection of individual cows and 41 herd-level management-related risk factors using univariable analyses. In this model, the continuous OD value was used to estimate the probability of infection, corrected for known animal covariates and laboratory factors. The statistical significance of the potential risk factors was assessed by calculating odds ratios and their 95% credibility posterior intervals.

Four significant risk factors were identified: housing of cows in bed stalls compared to housing in tie stalls; low level of hygiene in the feeding area of calving areas; low amounts of straw in the bedding of the calving area; high animal density among young stock >12 months of age. Surprisingly, the hygiene level in the calving area was not found to affect the odds of infection.