Haemonchus contortus is one of the most pathogenic gastrointestinal parasites that infect small ruminants. The indiscriminate use of anthelmintics (i.e., benzimidazole class, BZ) to control infections has led to the reduction of drug efficacy in H. contortus populations worldwide. Resistance to BZ is associated with high frequencies of single nucleotide polymorphisms at F200Y, F167Y, and E198A positions of the β-tubulin isotype 1 gene. This study aimed to determine the frequency of single nucleotide polymorphisms associated with BZ resistance in H. contortus from 18 farms (545 sheep and 124 goats) in Paraná, Southern Brazil. Health management practices were identified as risk factors from individual farms. Genomic DNA was extracted from 20,000 larvae/farm and used in quantitative polymerase chain reaction assays for the three mutations. We ran a correlation analysis between flock health and quantitative polymerase chain reaction data. H. contortus was the most prevalent parasite in 67% (12/18) of the farms. Resistant allele frequencies were detected for F200Y (var. 46.4 to 72.0%) and F167Y (var. 15.7 to 23.8%). Only (100.0%) susceptible alleles were detected for the E198A. High treatment frequency (15/18), visual weight estimations for anthelmintic dose (15/18), no integration with other farm practices (14/18), treatment of all animals (14/18), and no quarantine period for newly acquired animals (10/18) were considered the most critical risk factors associated with BZ resistance. This is the first systematic prevalence study linking management practices on smallholder farms and the molecular data of BZ resistance of H. contortus in Southern Brazil.

Management of invasive vertebrate species often requires the use of lethal control tools such as toxins, traps, or shooting. However, because these pest species are sentient and have the capacity to suffer, the application of such tools raises concerns about welfare impacts. To address such concerns, research, policy and regulation have focused most often on the welfare impacts (humaneness) of the tools at the individual animal level (ie the ‘quality’ of the impact) with no attempt to assess welfare at the population level (ie the ‘quantity’ of the impact). Because control programmes often target large numbers of animals, we suggest that when the welfare costs of pest control operations and strategies are being evaluated, the numbers of individuals involved should be considered in addition to the intensity and duration of individual suffering. We explore this concept using a modelling framework and three New Zealand case studies (brushtail possums [Trichosurus vulpecula], ship rats [Rattus rattus], and Bennett's wallabies [Macropus rufogriseus]) to assess the extent to which typical control strategies used by land managers influence the numbers of animals killed. We test whether a predicted relationship between numbers killed and position on the population growth curve holds across these scenarios, and identify whether it would be economically viable for end-users to adopt more welfare-friendly control strategies (ie those that kill fewer individuals to achieve the required management outcomes) for these pest species, or whether some form of incentive would be required. Computer modelling showed that for four simulated brushtail possum control strategies, the number of animals killed on a 1,000-ha area over 30 years ranged from approximately 13,000 to 26,000. Similarly, for two ship rat control strategies, numbers killed over a 20-year period were 977 for an aerial strategy versus 1,517 for a ground-based strategy. For both species, the strategies that killed fewest animals generally also cost the least. For Bennett's wallabies, because farmers only carry out control for production benefits, the control strategy they are most likely to select would result in the highest number of wallabies killed. To reduce the number of wallabies killed while allowing farmers to achieve some production benefits, farmers would need to receive some additional financial benefit. The concept of welfare incentive then raises questions such as ‘what willingness is there to pay for increased welfare’ and ‘to what extent can reducing control costs substitute for incentive payments in reducing numbers killed?’

We present a model to optimise a vaccination campaign aiming to prevent or to curb a Zika virus outbreak. We show that the optimum vaccination strategy to reduce the number of cases by a mass vaccination campaign should start when the Aedes mosquitoes' density reaches the threshold of 1.5 mosquitoes per humans, the moment the reproduction number crosses one. The maximum time it is advisable to wait for the introduction of a vaccination campaign is when the first ZIKV case is identified, although this would not be as effective to minimise the number of infections as when the mosquitoes' density crosses the critical threshold. This suboptimum strategy, however, would still curb the outbreak. In both cases, the catch up strategy should aim to vaccinate at least 25% of the target population during a concentrated effort of 1 month immediately after identifying the threshold. This is the time taken to accumulate the herd immunity threshold of 56.5%. These calculations were done based on theoretical assumptions that vaccine implementation would be feasible within a very short time frame.

In 2008 as in previous four years, campylobacteriosis was the most frequently reported zoonotic disease in humans in the European Union (EU) with fresh poultry meat as one of the most important reservoir of human infection (EFSA, 2010a). The reduction of campylobacter prevalence and load in live poultry is believed to be one of the most effective ways of reducing the contamination of foodstuffs and the number of human campylobacter cases. On this purpose some European Member States adopted national campylobacter control or monitoring programs but a European strategy to reduce campylobacter is still missing. The first step in this direction has been a European Union-wide baseline survey carried out in 2008 at slaughterhouses to obtain comparable values of prevalence of campylobacter in broiler batches and on broiler carcasses for all Member States. Current pre-harvest strategies available to reduce campylobacter contamination in poultry production include the application of on-farm biosecurity measures, the decontamination of litter, and the supplementation of feed with compounds inhibiting campylobacter and the treatment of drinking water. Moreover, novel strategies, specifically targeting campylobacter control at pre-harvest level, are in progress, including administration of probiotics, vaccination, antibiotics used in combination with molecule able to prevent the emergence of antibiotic resistance and antimicrobial alternatives (i.e. bacteriophages, bacteriocins). This paper is an overview on pre-harvest control strategies.

A fundamental study on the control of hydraulically actuated robots is presented. Dynamic modelling is performed in both time-domain and frequency-domain. It is shown that the inclusion of hydraulic elements increases the order of the system. Hydraulic compliance is the most effective factor in this regard.

Three distinct control strategies are applied. Their performances are evaluated and compared. All three methods are exemplified with a two link hydraulic robot in a computer simulation. The robot has the same hydraulic configuration as many existing industrial manipulators. The simulation program is written in ACSL (Advanced Continuous Simulation Language) running on a VAX 11/750.

It is standard now in undergraduate and graduate courses in robotics to teach the basic concepts of position control design strategies. Due to the geared motors inherent in most educational and industrial manipulators, sophisticated control design strategies such as the inverse dynamics technique cannot be easily demonstrated in a laboratory setting. A direct drive 5-bar-linkage manipulator with reduced motor torque requirements is proposed in this paper for such a purpose. The manipulator dynamics are easily understood by undergraduates and an inverse dynamics control strategy is suggested which can be easily designed by students at the undergraduate level.

In the paper we address a problem of controlling an oscilmotion with a robot. As the object we have selected a yo-yo. First we have measured and analysed the motion of different yo-yos. We have developed a simplified model of a yo-yo which has one degree-of-freedom, and the behaviour at the end of the string is modelled as an impact. Next, we discuss the control strategy. Our results show, that for playing a yo-yo it is important to start the upward motion before the yo-yo reaches the bottom position and the acceleration has to be reversed after the bottom impact. We present two control strategies: one based on predefined hand motion pattern and and the other generating the hand motion on-line. Both allow playing the yo-yo at a selected top height. The theoretical results have been proven by experiments on a real robot system.

A wheeled mobile manipulator system is modeled using Kane's dynamic equations. Kane's equations are constructed with minimum effort, are control oriented and provide both physical insight and fast simulations. The powerful tools of Kane's approach for incorporating nonholonomic motion constraints and bringing noncontributing forces into evidence are exploited. Both nonholonomic constraints associated with slipping and skidding as well as conditions for avoiding tipping over are included. The resulting equations, along with the set of constraint equations provide a safe and complete framework for developing control strategies for mobile manipulator systems.

In this paper we discuss several established and potential animal models for human parasitic infection, with a focus on rodent, pig and primate models and the nematodes Ascaris, Trichuris and Toxocara spp. Firstly, we discuss the relevance of choosing a suitable animal host to fit the particular study hypothesis, and the interaction between mathematical modelling and animal models. Secondly, we review the use of animal models for the study of nutrition-parasite interaction, evaluation of treatment and control strategies, and bacteria-parasite interactions. We show that rodent, pig and primate models are all very useful in parasitological research, and that each model has its limitations. However, based on recent experience with the pig-Ascaris and pig-Trichuris models, a more extensive use of the pig-parasite model is advocated, especially for the study of the interaction between human malnutrition and helminth infection, and congenital helminth infection.

This paper contains the result of a computer simulation of the dynamic performance of a manipulator. Provision is made in the program developed to represent the manipulator in either a redundant or non-redundant form. The models derived are used in simulation studies to evaluate the dynamic behaviour of the process when subjected to different control strategies for a range of operational tasks. The dynamic manipulator model presented is derived from the laws of Newtonian and Lagrangian Mechanics.

Progress in the development of a simple life cycle model, with both deterministic and stochastic components for the brown ear tick, Rhipicephalus appendiculatus Neuman (Acarina: Ixodidae), is described. Control strategies or interventions that are user-manipulated are incorporated.

The model is initially applicable to Rusinga Island, Lake Victoria, Kenya, where parasitic phase data have been accumulated for a 30-months' period, but could be used for any other R. appendiculatus locations.

About 70 insects and five mites regularly or occasionally infest the cotton crop in subtropical Africa. The economic importance of these pests varies according to the climate and cropping pattern in the region. Cotton aphid, Aphis gossypii Glover and yellow tea mite, Polyphagotarsonemus latus (Banks) as foliage feeders and three bollworms, Pectinophora gossypiella Saunders, Diparopsis watersi Roths, and Heliothis armigera Hbn., during boll formation and development, are major pests. Pesticides have been used extensively to suppress the pest populations and infestation levels in the crop. Natural enemies of certain pests occur in the region, nevertheless, their effectiveness in pest control is not well-known or fully exploited. Research on yield loss evaluation, pest ecology, varietal resistance and cultural practices is underway in several countries. Therefore, a global pest management in cotton is discussed in the context of local conditions and perspectives are highlighted.

The elegant grasshopper, Zonocerus elegans Thunberg, occurs in large numbers in Kilosa district during the dry season June to January and attacks a wide range of wild and crop plants. Its impact as a pest of crop plants becomes more noticeable from the middle of the dry season when the hoppers are well advanced and the only alternative food available are vegetables in backyard gardens and river valleys. The grasshopper damage continues throughout the vuli (short) rains until the end of the oviposition period in January, thus limiting the production of green vegetables in the district. A study on the biology and ecology of the pest in Kilosa district with emphasis on short term control strategies was started in 1987. Spot spraying with insecticides to kill the early instars was found to be effective, but area-wide implementation was necessary to prevent re-invasion of cleared areas.

Lepidopterous stem borers constitute one of the major constraints to cereal crop production in southern Africa. Chilo partellus Swinhoe, is an economically important stem borer of maize and sorghum. Current research status on C. partellus is reviewed and substantial advances in the distribution, bioecology and control strategies are discussed. Present work on the assessment of crop losses, elucidation of mechanisms of resistance, development of resistant crop cultivare, feasibility of biological control measures and the implementation of other stem borer management methods are reported. Further areas of research into the management of C. partellus are identified.

Malaria, African trypanosomiasis, theileriosis, babesiosis and coccidiosis are of great public health and/or economic importance in eastern Africa. Leishmaniasis is an increasing problem in this area and other protozoal diseases which are found among human and/or livestock populations include toxoplasmosis, trichomoniasis, amoebiasis, giardiasis, sarcocystosis, Balantidium coli infection and histomoniasis.

Control of the vector-borne parasitic protozoan diseases has been based mainly on the use of pesticides with their attendant, adverse effects on the environment.

The paper describes the public health and economic problems posed by the main protozoan diseases in eastern Africa and discusses their control, stressing the importance of environmental considerations when planning control measures. Further, a consideration of the public health impact of these diseases when drawing up, and during implementation of, major agricultural, hydro-electric or irrigation schemes, is emphasized. The possible effects of control measures on the social and economical welfare of local communities is highlighted.

Among several species of insect pests that attack the millet crop, the earhead caterpillar, Raghuva albipunctella de Joannis and Acigona ignefusalis Hmps., are considered the major pests. The constraints against the successful implementation of an integrated pest management programme of these insects are examined. The relative importance and significance of host plant resistance in such a programme is compared against other modalities.

The use of insecticides is negated by lack of cash value returns, water supply, trained personnel and poor delivery system. Cultural practices, such as the synchronisation of early planting, destruction of harvest residues and end-of-season ploughing, have the potential for reducing carry-over populations. However, the difficulties in their implementation range from farmer education and efficiency to changes in traditional practices and introduction of new labour intensive practices after harvest. While it appears that natural enemies are taking a gradual toll on R. albipunctella, they appear inefficient in controlling A. ignefusalis. A range of plant characters have been identified: tillering in certain varieties as a form of tolerance to borers; maturity cycles that result in escape (pseudo-resistance) from Raghuva infestation, hairiness in relation to preference for oviposition and head compactness in deterring larval penetration into millet heads. Most of these characters are common in landrace types. The real problem appears to be one of incorporating and utilising the identified resistance into germplasm sources which possess other desirable agronomic characters that the farmer requires. This implies multi-disciplinary effort which is the basis for integrated pest management. In most of Africa, and in the Sahel in particular, this basis is remotely present.