Temporal and spatial patterns of African swine fever in Sardinia

Temporal patterns and spatial distribution of African swine fever (ASF) were studied through the analysis of routinely collected data in the ASF-endemic area of the Province of Nuoro, Sardinia. During 1993–1996, ASF outbreaks were reported from 45 out of the 82 municipalities of the study area. Overall farm-level incidence rate (IR) was 1.3 outbreaks per 100 farms-year. ASF peaked in 1995 (IR=1.8) and declined in 1996 (IR=0.82). Significant (P<0.05) spring peaks of ASF outbreaks and affected municipalities were detected using statistical methods for circular distributions. Spatial clustering of ASF-affected municipalities, as evaluated by join-count statistics, was significant in 1993 (Z_jc=−3.0, P<0.01) and 1994 (Z_jc=−3.2, P<0.01) but not in 1995 (Z_jc=−0.6, P=0.55) and 1996 (Z_jc=−1.2, P=0.23). Extensive pig farming and ASF were spatially co-distributed (κ=0.51, 95% CI=0.33–0.70).     

Bartonellae of the Namaqua rock mouse, Micaelamys namaquensis (Rodentia: Muridae) from South Africa

The aim of this study was to determine Bartonella prevalence and diversity in Namaqua rock mice, Micaelamys namaquensis, a species endemic to South Africa, which can attain pest status. A total of 100 heart samples collected monthly from March to December were screened for Bartonella genome presence using three primer sets targeting the citrate synthase (gltA) gene, the NADH dehydrogenase gamma subunit (nuoG) gene and the RNA polymerase β-subunit-encoding gene (rpoB). An overall prevalence of 44% was obtained, with no statistically significant differences or correlations between infection rates and rodent sex, month of capture or season of capture. Phylogenetic analysis of 34 unambiguous gltA sequences revealed the presence of three discrete Bartonella lineages in M. namaquensis, one of which corresponds to Bartonella elizabethae, a species with known zoonotic potential.     

Temporal and spatial dynamics of mineral levels of forage,soil and cattle blood serum in two semi-arid savannas of South Africa

In this study, we examined temporal and spatial dynamics of minerals of forage, soil and cattle serum in two savannas (valley and plain) of South Africa. The aims were to explore the relationships between ecosystem components, and plan communal grazing and fodder flow for sustainable livestock production. In each area, grazing sites near, at intermediate distance from (middle) and far from homesteads were selected. In the valley land, site interacted with season to influence local variations (P<0.05) of soil calcium and microelements. In the plain lands, local variations occurred for soil phosphorus and magnesium. At the large scale, most macro-minerals showed differences between the valley and plain lands. In the valley areas, forage calcium differed (P<0.05) locally in the dry season, whereas in the plain areas, potassium and phosphorus showed local variations (P<0.05) in the wet season. Seasonal variations of most forage elements were significant within each local site of both study areas. All forages were deficient in phosphorus and copper. Cattle serum from the valley area had low iron concentrations. The study concluded that biotic and abiotic factors may influence the distribution of soil and forage elements, but their effects may vary between the two areas. Rangeland improvement and supplementation strategies are suggested to sustain animal production.     

Seasonal abundance and distribution of Parafilaria bovicola ovipositional blood spots on cattle in South Africa

More than 23 000 cattle of both sexes and different ages were examined for blood spots caused by egg-laying females of P. bovicola. Although these studies extended over four years and involved 5 farms in different parts of the Transvaal Bushveld, the overall results were the same. Ovipositional bleeding was strongly seasonal with blood spots first appearing in winter (June), reaching a peak in spring (September-November) and thereafter declining rapidly as summer progressed. In a single year at Zoutpan Research Station up to 92,1% of the 1st year heifers had already bled by November and this proportion increased only slightly to 95,1% by the end of the bleeding season (May). The number of blood spots per animal showed a similar seasonal abundance except for a second peak of abundance in June for 1st year heifers and oxen. The prevalence of blood spots in cattle of different ages and sex varied markedly. At Mara Research Station half as many oxen bled in their 2nd year as in their 1st year, while at Zoutpan 19,2% fewer heifers bled in their 2nd year than in their 1st. Bulls bled the most, then 1st year oxen, 1st and 2nd year heifers and 2nd year oxen, with breeding cows bleeding the least. A high female hormone level appears to be associated with the development of immunity. The shortest period from birth to 1st blood spot (the apparent prepatent period) was 191 days, while 81,8% of oxen bled for the 1st time within 279 days after birth.(ABSTRACT TRUNCATED AT 250 WORDS)     

Milk utilisation patterns in the low-input production systems in South Africa

Understanding the utilisation patterns of milk assists in designing appropriate dairy development schemes in rural communities. The objective of the study was to determine milk utilisation patterns in different smallholder farming systems in the Eastern Cape Province of South Africa. Data were collected through the administration of recording sheets to 130 randomly selected households in Alice, Fort Beaufort and Queenstown districts. Amounts of milk produced per household ranged from 9 to 21 l per household per day. Milk consumption/household/day was similar among the three districts. Milk consumption in the early lactation doubled the amount consumed in late lactation (P < 0.05). Milk in the communal areas was largely utilised as fresh or sour milk. Fresh milk was mostly used in tea/coffee or to make porridge for children. Sour milk was consumed with thick boiled maize meal. Fort Beaufort (10.2 ± 1.37 l/day) had the highest sour milk sales whilst Queenstown had the highest fresh milk sales (9.7 ± 5.57 l/day). It was concluded that quantities of milk consumed or sold as fresh or sour were generally low and varied across smallholder farming systems.     

Waterfowl abundance and diversity in relation to season,wetland characteristics and land-use in semi-arid South Africa

We studied waterfowl abundance and diversity in relation to season (wet vs dry), wetland characteristics (vegetation and morphometrics) and land-use in a semi-arid agricultural region of South Africa to determine how waterfowl respond to various wetland characteristics, particularly those of permanent agricultural ponds.Wetlands were visited during the wet (n = 215) and dry (n = 178) seasons of 1997 and species' abundances, and wetland and upland characteristics were recorded. Canonical correspondence analyses and multiple regressions determined which wetland and upland characteristics were most strongly associated with waterfowl density and species richness for both the wet and dry season. Overall, diving ducks were not abundant in the wet season, and were rare to absent in the dry season. Divers only responded positively to the characteristics of natural wetlands, including greater surface area, percent coverage of emergent vegetation, and high (ungrazed) shoreline vegetation. Of six species of dabbling ducks present during the wet season, occurrence of three co-varied with wetland and upland characteristics associated with agriculture, namely permanent water, and agricultural grains in the dry season. Being largely grazers, geese responded positively to the higher proportions of bare shoreline, characteristically surrounding agricultural ponds. Because only a few species associated with artificial waterbodies, natural wetlands should be conserved to protect waterfowl diversity in semi-arid South Africa.     

Sexual disparity in activity patterns and time budgets of angulate tortoises (Chersina angulata) on Dassen Island,South Africa

Behavioural frequencies and time budgets for male and female Chersina angulata were recorded in spring, September 2004. The daily activity of the population was 10.51 ± 0.42 h (mean ± CI), but individual males and females were in the open for 2.57 ± 1.12 h and 1.58 ± 1.44 h, respectively. Both sexes spent nearly 3.5 h per day basking with 90% of the basking time in the cover of sparse vegetation. Feeding and walking were the most frequent active behaviours. The activity pattern of the sexes differed between 10:00 and 12:00 in the morning when males spent more time out of cover on active behaviours, particularly feeding, than females did. The daily activity pattern of the population peaked between 10:00 and 12:00, reflecting the activity pattern of the more active sex, males. Females were out of cover, active, and feeding at higher temperatures than were males. The high temperatures probably allowed females to complete activities more efficiently, reducing their exposure time and predation risk. Although fighting and mating represented small fractions of male time budgets, the extended physical presence through walking and feeding may help males to establish dominance hierarchies and enhance mating success.     

Protein kinase C isoforms in the porcine corpus luteum: Temporal and spatial expression patterns

Porcine corpora lutea (CL) fail to show a luteolytic response to prostaglandin-F-2α (PGF-2α) (ie, luteolytic sensitivity, or LS) until ∼day 13 of the estrous cycle. In view of the importance of protein kinase C (PRKC) in PGF-2α signal transduction, it was hypothesized that limiting levels of 1 or more PRKC isoforms may explain the lack of LS before day 13. This hypothesis was tested by examining expression of mRNA and protein, and the cellular localization patterns of the 11 PRKC isoforms throughout the porcine estrous cycle, to determine whether PRKC expression correlates with and thus may be associated with the control of the acquisition of LS in the pig. The expression patterns show that for most PRKC isoforms (ie, PRKC alpha, beta 1, beta 2, delta, epsilon, theta, iota, and zeta), mRNA was maximally expressed on day 7 or day 10 (protein kinase D1 only) of the cycle, whereas PRKCs gamma, eta, and lambda were unchanged. At the protein level, only PRKC epsilon (PRKCE) significantly changed during the estrous cycle and was elevated on day 13 (versus days 4, 7, and 15; P < 0.05). By immunofluoresence, most PRKC isoforms, including PRKCE, were localized to steroidogenic large luteal cells (LLC) and small (nonendothelial cell) luteal cell subtypes (SLC). In conclusion, since the increase in PRKCE protein expression (day 13) occurred coincidentally with the onset of LS (≥day 12), these results support a potential role for PRKCE in control of the acquisition of LS in the pig.     

Breeding season and breeding potential of the greater cane rat (Thryonomys swinderianus) in captivity in South Africa

The cane rat, Thryonomys swinderianus, is an aseasonal breeder. It has a very low fecundity rate with an average litter size of 2.9 (range 1-5), producing a maximum of two litters per annum. The low annual fecundity is the direct result of the extended gestation period of the cane rat which exceeds 150 days in duration.     

2005-2014年内蒙古草地火灾排放污染物的时空格局

火是生态系统重要干扰因子并对大气环境和人类健康有显著影响。该研究基于2005-2014年内蒙古地区MODIS遥感卫星火点数据,结合畜牧业统计年鉴,估算各区域草地火燃烧生物量,运用排放因子法、核密度法和克里金插值法,估算10年间内蒙古地区草原排放污染物总量及时空分布。研究结果显示,内蒙古地区草地生物质密度存在显著差异,由东北到西南呈递减趋势。此外,内蒙古地区草地火时空分布不均匀:草地火年变化呈阶梯式上升趋势,月变化呈双峰分布,火灾多集中3-4月和9-10月;空间上,火点密度从东北向西南逐渐递减。呼伦贝尔、兴安盟、通辽、赤峰、锡林郭勒盟、乌兰察布、包头、呼和浩特、巴彦淖尔、鄂尔多斯、乌海和阿拉善盟分别占区域总火灾次数的48.1%、7.4%、2.8%、1.9%、8.3%、3.8%、4.3%、1.2%、1.0%、20.6%、0.3%和0.3%。内蒙古地区草地火灾排放污染物CO₂、CO、NO_X、CH₄、VOC_S、PM_2.5、OC和EC总量分别为:658.31 kt、39.09 kt、846.18 t、1.22 kt、1.87 kt、2.49 kt、1.65 kt和197.96 t。此外,各污染物排放在时间和空间上不均衡,且与草地火密度的时空分布密切相关。该文通过对内蒙古地区草原火释放污染物的时空变化研究,为深入揭示草原火对区域环境的影响提供数据支持。     

Diurnal activity patterns of Glossina brevipalpis and G austeni (Diptera: Glossinidae) in South Africa, with reference to season and meteorological factors

Studies on the diurnal and seasonal availability of Glossina brevipalpis Newstead and G. austeni Newstead to stationary targets were conducted in north-eastern KwaZulu-Natal, South Africa. G. brevipalpis showed a bimodal, and occasionally trimodal, partly crepuscular cycle. Periods of the availability of flies to stationary, odour-baited targets (here referred to as diurnal "activity" patterns) were mainly early in the morning and late afternoon until dark, especially at dawn and dusk. The main diurnal activity period was the late afternoon peak, which occurred during the 1-2 h before sunset until dark. The amplitude of the morning and afternoon peaks seemed to be mainly modulated by temperature. This species was also active throughout the remainder of the day, depending on the season. Glossina austeni was day-active and activity seemed to increase with increasing temperature and decreasing relative humidity (RH). The species remained available to targets throughout the day, but during the hottest part of the day the diurnal pattern decreased somewhat, resulting in a U-shaped but still more or less unimodal pattern. The diurnal pattern was strongly modulated by ambient temperature, although seemingly more by a combined temperature-RH effect. Both species' availability to targets ceased after dark, although night activity was observed on various other occasions. The use of artificial refuges for G. brevipalpis and G. austeni as a possible means of escaping climatic extremes is briefly discussed and speculated on.     

Pasture problems in South Africa

Grassland problems in South Africa are reviewed and the suggestion made that a Pasture Research Institute should be established forthwith to serve South Africa. An holistic approach is needed whereby plant, soil and animal influences are studied as controllable parts of the environment. The importance of a legume component is stressed as also is the value of an examination of the whole range of potentially adaptable plant materials (exotic and indigenous). Plant breeding programmes must be a corollary of these studies. Reference is made to sward density as a factor in erosion control. Conservation of fodder is discussed in relation to drought conditions and the need is stressed for more information in relation to food quality both in the green state and when conserved. Pasture research is dealt with in relation to the huge potential offered in South Africa for the increase in the output of meat, milk and wool.     

Turkey meningo-encephalitis in South Africa

Turkey meningo-encephalitis is a neuroparalytic disease of turkeys first described and shown to be caused by a flavivirus in Israel. During 1978 a similar disease was observed in South Africa. In addition to the lesions described in Israel, myocarditis, regression of the ovary and egg peritonitis were constant findings. The similarity in host range, symptoms and pathological changes produced by the virus isolated locally and in Israel and the serological cross-reaction between the 2 virus isolates indicate that they are identical.     

Pasture research in South Africa

The “systems approach” means that decision‐rich parts of any given system are considered quantitatively and in their proper context. This is done by using models of various kinds. A model can be built if an adequate information base exists for the system in question, and if decisions have been taken about the scope and focal point(s) of the model, its application, and its form. The systems approach is illustrated by outlining a general procedure for livestock enterprise planning. Some of the research and extension problems revealed, and new problems created, by this and other models, are mentioned.

Two matters of general concern are discussed. It is argued that the quality of leadership in agricultural research leaves something to be desired. Secondly, the class of agricultural scientists seems to be regrettably indifferent to the long‐term effects of its work, and blind to the needs of primitive food producers. The systems approach can contribute to improvement in both areas, as a result of forcing people to define clear objectives and order their priorities. There is a need for grassland and other research workers to state the objectives of their disciplines for the next 30 years.     

The life-cycle and seasonal abundance of Echinoparyphium montgomeriana n. sp. (Trematoda: Echinostomatidae) in Natal,South Africa

A new species of Echinoparyphium, E. montgomeriana, is described from Durban, South Africa. Certain unusual aspects of its morphology are discussed. The adult fluke is a parasite of the alimentary tract of birds. Its larval stages are common parasites of freshwater snails belonging to the family Planor-bidae including Buiinus africanus,the intermediate host ofSchistosoma haematobium and S. mattheei in the area. These intra-molluscan stages are shown to have a seasonal transmission cycle.     

Seasonal abundance of adult ixodid ticks infesting cattle belonging to resource-limited farmers in the north-eastern Free State Province of South Africa

A study was undertaken to determine the seasonal abundance of the ticks infesting cattle owned by resource-limited farmers in the north-eastern Free State Province of South Africa. Infestations of Boophilus decoloratus Koch, 1844, Rhipicephalus evertsi evertsi Neumann, 1897, Rhipicephalus follis Donitz, 1910, Rhipicephalus gertrudae Feldman-Muhsam, 1960 and Rhipicephalus warburtoni Walker & Horak, 2000, were monitored on cattle of mixed breeds at monthly intervals from May 1998 to April 1999. High tick intensity on the cattle was observed between March and June, with a peak in May to June 1998 for B. decoloratus and R. evertsi evertsi. Few ticks from the other three species were recovered from the cattle. Small peaks in November to December 1998 for R. warburtoni, and in December 1998 for R. follis and R. gertrudae were observed. Following the winter (June to August), numbers of B. decoloratus declined markedly, while those of R. evertsi evertsi and other rhipicephalids increased. These results represent the first published information on ticks of veterinary importance infesting cattle in the north-eastern part of the Free State Province.     

Estimating the distribution and abundance of Rhipicephalus appendiculatus in Africa

The brown ear tick Rhipicephalus appendiculatus is responsible for transmitting the parasite Theileria parva in eastern, central and southern Africa, where it causes East Coast fever, Corridor disease and January disease in cattle. In an effort to assess the impact of these diseases and their control on livestock production in the region, studies are underway to model the factors controlling the distribution of the vector tick. Three recent studies have attempted to quantify and evaluate the variables influencing the distribution of R. appendiculatus, and these are reviewed and discussed in this paper.

The relationship between the distribution of an ecoclimatic index of suitability for the tick, calculated by the model CLIMEX on a 25 km² interpolated climate database for Africa, and of recorded observations of the tick itself, are evaluated. The sensitivity and specificity of the ecoclimatic index were calculated as 70.2–82.6% and 69.4–84.7%, respectively. In addition, addition, satellite-derived mean maximum normalized difference vegetation index (NDVI) for 1987 was assessed as a predictor of R. appendiculatus habitat in eastern Africa, by comparing the distribution of NDVI values in areas in which the presence of the tick has and has not been recorded. Some visual correlation was observed between mean maximum NDVI values of 0.15 or greater and known R. appendiculatus distribution in Kenya. In addition, this range of NDVI values corresponded closely to areas in Ethiopia where the tick does not occur but for which climatic suitability was predicted by CLIMEX. However, these NDVI values should not be considered universal predictors of habitat suitable for R. appendiculatus, and further study of the NDVI with ground truthing of habitat is considered necessary.