Good Farm Management Practices Research Articles

Parasitism and rumen impaction in a 5-month–old Yankasa ewe: A clinico-pathological report

We report concurrent acariosis, helminthosis and foreign body rumen impaction of multiple aetiologies in a 5-month-old Yankasa ewe from a multispecies flock on semiintensive management system. The clinical findings were tachycardia, hypothermia, bradypnea, diarrhoea, emaciation, lethargy, pale mucous membranes, and heavy tick infestation attached to the skin of the forelimb, hind limb, inguinal region, and the ears. Severe non-regenerative anaemia, marked neutrophilia and lymphocytopenia characterized the blood picture. The ewe was treated for endo and ectoparasites, along with fluid therapy. However, the ewe died in the course of treatment and the carcass was subsequently presented for necropsy. Gross findings included the presence of numerous ticks attached to the skin of the outer ears and interdigits, indigestible foreign materials in the rumen and numerous worms in the rumen, abomasum and the intestine. Laboratory analysis revealed that the ticks were Rhipicephalus sp. and Amblyomma sp. The rumen worms were identified as Paramphistomum sp., the worms from the abomasum were identified as Haemonchus contortus, and those of the intestine were identified as Moniezia expansa. Histopathologically, there was hypertrophy of the chief cells of the abomasum. There was a section of Haemonchus contortus surrounded by eosinophils within the mucosa of the abomasum. The villi of the intestine sloughed-off into the lumen. Based on the clinicopathological findings, the diagnoses of acariosis, helminthosis and foreign body rumen impaction were arrived at. The remaining animals in the herd were treated accordingly and the farmer was advised to ensure good farm management practices.

Sero-epidemiology of bovine tuberculosis in dairy cattle in Chattogram, Bangladesh

Mycobacterium bovis-caused bovine tuberculosis (bTB) is a global public health concern and commercially significant zoonotic disease. Many wild and domesticated animals, including cattle, are susceptible to this fatal disease and play an important role in cross-species transmission. To gain a better understanding of bTB in dairy cattle, a bTB serological study is also necessary in order to identify efficient bTB control strategies in Bangladesh. In Bangladesh, however, seroepidemiological research is either non-existent or limited (particularly Chattogram). To determine the seroprevalence of bTB and related possible risk factors in dairy cattle, a serological cross-sectional study was conducted (both animal and farm level). We estimated the seroprevalence of bTB was 7.5%(N=442) in this investigation, which also identified one animal-level and two farm-level possible risk factors. Individual animal risk factors included cattle source (own stock: OR=3.4, 95% CI: 1.4-8.1, p=0.006), and farm risk factors included population size (Larger: OR= 26.2, 95% CI: 2.2-319.1, p=0.010) and stocking density (Low and moderate: OR=19.6, 95%CI: 1.5-261.5, p=0.024). In the face-in housing system, there was also a higher risk of bTB seropositivity (OR=4.5). The research's key findings are thoroughly explored, and the findings will aid in the prevention and control of bTB in Bangladesh. In addition, early detection of positive cases, as well as their prompt removal and good farm management practices, can assist in preventing the spread of bTB to new human or bovine hosts. In underdeveloped nations like Bangladesh, a coordinated effort with local public health officials is critical for implementing an efficient TB control program.

Risk factors associated to bovine brucellosis seroprevalence in the eastern region of Paraguay.

In Paraguay, whose main economic activity is cattle raising, bovine brucellosis is an endemic disease. Between May 2019 and October 2020, a national prevalence survey was implemented by the Paraguayan Veterinary Services. In the frame of that survey, a cross-sectional study was conducted in the eastern region of Paraguay to identify the risk factors that could be associated with brucellosis-positive farms and to estimate the bovine brucellosis seroprevalence and farmers' awareness about the disease. A questionnaire was administered to farmers to collect data on potential risk factors for bovine brucellosis as well as awareness on the disease. A logistic regression model was used to identify the risk factors associated with a farm brucellosis positive status. Blood samples were collected from 2551 cattle on 133 farms. The overall apparent seroprevalence was 27.8 % (95 % CI: 20.4-36.3 %) at the farm level, and 5.5 % (95 % CI: 4.7-6.5 %) at the animal level. Among 18 potential risk factors, four were associated with a farm brucellosis positive status. Farm size was associated with a higher risk of positive status in medium (20-80 cows) and large farms (>80 cows), compared with small farms (<20 cows). Barn disinfection had a protective effect on the risk of positive status. Conversely, presence of dogs and not incinerating/burying aborted material increased this risk. Even if 89 % of the farmers acknowledged being aware of the bovine brucellosis transmission to humans, only 46% of these farmers declared using protective gloves during calving or when handling abortions. The findings of this study emphasize the importance of implementing biosecurity measures and proper disposal of aborted material to control the disease. Therefore, to control the disease in Paraguay, vaccination campaigns should be accompanied by awareness campaigns addressing good farm management practices to minimize the risk of introduction and maintenance of brucellosis as well as the risk of human infection.

Mapping the effect of antimicrobial resistance in poultry production in Senegal: an integrated system dynamics and network analysis approach.

The impact of antimicrobial resistance (AMR) extends beyond the farm-level to other stakeholders warranting the need for a collaborative approach to combat AMR while optimising production objectives and safeguarding human health. This study maps out the effect of AMR originating from poultry production in Senegal and highlights the entry points for interventions from stakeholders' perspectives. A causal loop diagram (CLD) was developed following a group model building procedure with 20 stakeholders and integrated with network analysis by translating the CLD into an unweighted directed network. Results indicate that with an eigenvector centrality of 1, 0.85, and 0.74, the production cost, on-farm profit, and on-farm productivity, respectively are the most ranked influential variables driving the complexity of AMR in the poultry production system. Two reinforcing feedback loops highlight the dual benefits of improving on-farm productivity and increasing on-farm profit. However, one balancing feedback loop that revolves around the causal link between producers' investment in qualified human resource personnel to ensure good farm management practices underline the financial implication of producers' investment decisions. The findings provide precursory groundings for the development of a quantitative SD model, the formulation of intervention scenarios and ex-ante impact assessment of the cost-effectiveness of the interventions.

Production of recombinant proteins including the B-cell epitopes of autolysin A of Staphylococcus aureus isolated from clinical sheep mastitis and their potential for vaccine development.

Staphylococcus aureus is the most common clinical mastitis-associated pathogen in sheep which contributes to reduced welfare of affected animals and, therefore, compromises the quality and quantity of milk production. To prevent mastitis and its spread, it is essential to guarantee adequate breeding conditions and animal health, through the adoption of good farm management practices and the application of suitable biosecurity measures. Vaccination can play a strategic role in prevention, control, and eradication of diseases. The identification of secreted and cellular antigens of the predominant sheep-CC130/ST700/t1773 lineage would assist in the design of effective vaccine against mammary infections caused by S. aureus. In the current study, we carried out a 3D structural prediction analysis with the identification of the best B cell epitopes of the whole and secreted portion of S. aureus AtlA. Fragments of atlA, containing the main predicted epitopes, were amplified, cloned, and expressed in Escherichia coli for recombinant protein production. Two selected clones produced recombinant proteins (rAtl4 and rAtl8) showing strong reactivity with a hyperimmune serum against the native AtlA and with blood sera collected from sheep with clinical S. aureus mastitis. These may represent potential candidate protein-based vaccines able to elicit a protective immune response to be evaluated by vaccination and subsequent challenge of the vaccinated sheep.

Isolation and antibiotic sensitivity of Salmonella typhimurium isolates from poultry farms and slaughterhouses of Chitwan, Nepal

Nepalese poultry sector is progressing rapidly contributing around 4% of GDP with flourishing impact to provide sustainable and cheapest protein as source of human food. However, with the accelerating pathway, this industry is shed-back by outbreak of several infectious and zoonotic diseases impacting huge economic losses. Salmonella also cause infection in poultry birds and constitutes the largest reservoir of Salmonella organisms in nature. S. typhimurium is an unadopted serotype of Salmonella that may be transmitted to human, animals (poultry) and environment from contaminated food, feed and water. Use of antibiotics, good farm management practices and biosecurity are the treatment and control measures of this disease in poultry production. Development of antibiotic resistant strains of S. typhimurium thus not only pose considerable threat to clinicians, but is also of public health concern as these resistant strains after ingestion are capable of transferring resistance to other pathogens. The present study was undertaken to determine prevalence and antibiotics sensitivity of S. typhimurium strains isolated from domestic poultry from Chitwan, Nepal. Out of 79 farm and 23 chicken slaughterhouse sampling sites, the 107 (19.45%) out of 550 cultured specimens were confirmed for S. typhimurium. Amongst various antibiotics used for in vitro sensitivity testing, the two antibiotics: Colistin (Cl) and Enrofloxacin (Ex), were found to be 100% effective, whereas out of 22 antibiotics, 18 antibiotics showed weak to strong resistance pattern against S. typhimurium isolate. In the present study, Polymyxin and fluoroquinolone antibiotics were found to be most effective against S. typhimurium. Understanding the source of exposure to pathogens (especially resistant pathogens) provides some insight into antibiotic use and misuse in the region. Looking through the lens of One Health approach, the regulation of antibiotic use in animal medicine has direct implications for human health through the increased resistance of foodborne pathogens to vital antibiotic therapy. Thus, judicious use of antibiotics based on their sensitivity pattern should be practiced.

Assessment of Biosecurity Status of Broiler Farm at Jamalpur District.

Broiler chicken production is an important source of animal protein supply, but the biosecurity conditions of Jamalpur region are not satisfactory. This study was done to gauge farmers' knowledge of and adherence to biosecurity guidelines of a broiler farm. We visited five randomly selected farms in two unions of Jamalpur district. The questionnaires were developed based on “biosecurity guideline for commercial poultry industry in Bangladesh”, provided by the department of livestock services of Bangladesh. There were 143 parameters, and each one of them bears 1 point. For each parameter that a farm followed, it gained one (1) point. The parameters were divided into 5 different principles: isolation, good farm hygiene, flock health care and monitoring, good farm management practices, and compliance with government regulations. Farm hygiene and compliance with government regulations were most commonly ignored principle by all the farms, especially in case of farm worker’s hygiene All the farm had trees adjacent to the shed. The highest score was 62 (43.37%), gained by Farm 2, and the lowest point was 37 (25.87%) gained by Farm 1. The average score was 50 (34.97) points. This is the first survey work in this region, but there were difficulties in working with a larger number of farms due to the COVID-19 pandemic with frequent lockdowns. This study may help to improve the biosecurity conditions of broiler chicken production in small stockholders of this region.

Occurrence of Aflatoxin in Dairy Cow Feed Ingredients and Total Mixed Ration

Abstract. The level of aflatoxin B1 (AFB1) in dairy cow feed ingredients and Total Mixed Rations (TMRs) procured at two farms for low- and high-yielding dairy cows were surveyed. Raw milk from the two groups of cows at each farm was sampled 24 h after feeding the cows with examined feedstuffs during both the rainy and the non-rainy season. The aflatoxin M1 (AFM1) level in the raw milk samples was measured 12-24 h later. The levels of AFB1 in feed and AFM1 in milk were determined by validated enzyme linked immunosorbent assay (ELISA). The influence of farm management and type of feeding system on aflatoxin occurrence were considered. AFB1 and AFM1 were detected in 100% of feed and milk samples, respectively. The average level of AFB1 in the feed ingredients and TMRs were in the range of 1.6-104.7 µg/kg and 11.0-56.0 µg/kg, respectively. The average level of AFM1 in milk samples was 77.0 ng/L. The average concentrations of AFB1 in feeds and AFM1 in milk procured in the rainy season were significantly greater than those procured in the non-rainy season (p&amp;lt;0.05). Of the studied feed, maize silage was determined as the most contaminated feed ingredient in terms of AFB1 content. Furthermore, the AFM1 in 75% of milk samples obtained from high-yielding dairy cows and 25% of milk samples obtained from low-yielding dairy cows indicated AFM1 level higher than the maximum allowable Europe Commission limit of 50 ng/L. The results also showed that the occurrence of AFB1 in feed varied with farm feed management. The extent of translocation to AFMI in milk samples was dependent on type of cow, whether low- or high- milk yielding. This study suggests regular risk analysis and using good farm management practices are important to control aflatoxin contamination in feed and milk. Keywords: Aflatoxin B1, Aflatoxin M1, Dairy cows, Feed, Milk yield.

Economic performance and efficiency determinants of crop-producing farms in Norway

Purpose The purpose of this paper is to explore the economic performance of Norwegian crop farms using a stochastic frontier analysis. Design/methodology/approach The analysis was based on a translog cost function and unbalanced farm-level panel data for 1991–2013 from 455 Norwegian farms specialized in crop production in eastern and central regions of Norway. Findings The results of the analysis show that the mean efficiency was about 78–81 percent. Farm management practices and socioeconomic factors were shown to significantly affect the economic performance of Norwegian crop farms. Research limitations/implications Farmers are getting different types of support from the government and the study does not account for the different effects of different kinds of subsidy on cost efficiency. Different subsidies might have different effects on farm performance. To get more informative and useful results, it would be necessary to repeat the analysis with less aggregated data on subsidy payments. Practical implications One implication for farmers (and their advisers) is that many of them are less efficient than the estimated benchmark (best performing farms). Thus, those lagging behind the best performing farms need to look at the way they are operating and to seek out ways to save costs or increase crop production. Perhaps there are things for lagging farmers to learn from their more productive farming neighbors. For instance, those farmers not practicing crop rotation might be well advised to try that practice. Social implications For both taxpayers and consumers, one implication is that the contributions they pay that go to subsidize farmers appear to bring some benefits in terms of more efficient production that, in turn, increase the supply of some foods so possibly making food prices more affordable. Originality/value Unlike previous performance studies in the literature, the authors estimated farm-level economic performance accounting for the contribution of both an important farm management practice and selected socioeconomic factors. Good farm management practices, captured through crop rotation, land tenure, government support and off-farm activities were found to have made a positive and statistically significant contribution to reducing the cost of production on crop-producing farms in the Central and Eastern regions of Norway.

Postgenomics Characterization of an Essential Genetic Determinant of Mammary Pathogenic Escherichia coli.

ABSTRACTEscherichia coli are major bacterial pathogens causing bovine mastitis, a disease of great economic impact on dairy production worldwide. This work aimed to study the virulence determinants of mammary pathogenic E. coli (MPEC). By whole-genome sequencing analysis of 40 MPEC and 22 environmental (“dairy-farm” E. coli [DFEC]) strains, we found that only the fec locus (fecIRABCDE) for ferric dicitrate uptake was present in the core genome of MPEC and that it was absent in DFEC genomes (P < 0.05). Expression of the FecA receptor in the outer membrane was shown to be citrate dependent by mass spectrometry. FecA was overexpressed when bacteria were grown in milk. Transcription of the fecA gene and of the inner membrane transport component fecB gene was upregulated in bacteria recovered from experimental intramammary infection. The presence of the fec system was shown to affect the ability of E. coli to grow in milk. While the rate of growth in milk of fec-positive (fec+) DFEC was similar to that of MPEC, it was significantly lower in DFEC lacking fec. Furthermore, deletion of fec reduced the rate of growth in milk of MPEC strain P4, whereas fec-transformed non-mammary gland-pathogenic DFEC strain K71 gained the phenotype of the level of growth in milk observed in MPEC. The role of fec in E. coli intramammary pathogenicity was investigated in vivo in cows, with results showing that an MPEC P4 mutant lacking fec lost its ability to induce mastitis, whereas the fec+ DFEC K71 mutant was able to trigger intramammary inflammation. For the first time, a single molecular locus was shown to be crucial in MPEC pathogenicity.

Detection of egg stains based on local texture feature clustering

The quality of egg is mainly influenced by the dirt adhering to its shell. Even with good farm-management practices and careful handling, a small percentage of dirty eggs will be produced. The purpose of this research was to detect the egg stains by using image processing technique. Compared to the color values, the local texture was found to be much more adept at accurately segmenting of the complex and miscellaneous dirt stains on the egg shell. Firstly, the global threshold of the image was obtained by two-peak method. The irrelevant background was removed by using the global threshold and the interested region was acquired. The local texture information extracted from the interested region was taken as the input of fuzzy C-means clustering for segmentation of the dirt stains. According to the principle of projection, the area of dirt stains on the curved egg surface was accurately calculated. The validation experimental results showed that the proposed method for classifying eggs in terms of stain has the specificity of 91.4% for white eggs and 89.5% for brown eggs. Keywords: eggs, eggshell dirt stains, computer vision, local texture feature, FCM, egg classifying DOI: 10.25165/j.ijabe.20181101.2592 Citation: Yang Q H, Jia M M, Xun Y, Bao G J. Detection of egg stains based on local texture feature clustering. Int J Agric & Biol Eng, 2018; 11(1): 199–205.

Macroinvertebrate assemblages in agricultural, mining, and urban tropical streams: implications for conservation and management.

The study evaluated the response of macroinvertebrate assemblages to changes in water quality in different land-use settings in Manyame catchment, Zimbabwe. Four land-use categories were identified: forested commercial farming, communal farming, Great Dyke mining (GDM) and urban areas. Macroinvertebrate community structure and physicochemical variables data were collected in two seasons from 41 sites following standard methods. Although not environmentally threatening, urban and GDM areas were characterised by higher conductivity, total dissolved solids, salinity, magnesium and hardness. Chlorides, total phosphates, total nitrogen, calcium, potassium and sodium were significantly highest in urban sites whilst dissolved oxygen (DO) was significantly higher in the forested commercial faming and GDM sites. Macroinvertebrate communities followed the observed changes in water quality. Macroinvertebrates in urban sites indicated severe pollution (e.g. Chironomidae) whilst those in forested commercial farming sites and GDM sites indicated relatively clean water (e.g. Notonemouridae). Forested watersheds together with good farm management practices are important in mitigating impacts of urbanisation and agriculture. Strategies that reduce oxygen-depleting substances must be devised to protect the health of Zimbabwean streams. The study affirms the wider applicability of the South African Scoring System in different land uses.

A Preliminary Study of Knowledge, Attitude and Practices of Pesticide Use Among Oil Palm Workers in Johor

Agricultural sector is a fundamental activity that has been practiced since the civilization of Babylonian, which also has been proven by the glory of Nile River Valley and Mekong Valley. History has shown that the migration of investors and foreign labors in Malaysia in 1960 was to be harvested fortune from the land due to its fertility and suitability. As a developing country, agriculture is one of the important sectors in Malaysia that contributes towards the national economy development. The mentioned sector has indirectly provided benefits both local and global perspectives either in terms of business opportunity as well as employment opportunity. In general, this study aims to assess the level of knowledge, practices and attitudes in the use of pesticides in oil palm plantation workers in Johor. The findings of this study will be used as reference in the farming industry, particularly for the awareness and understanding of good farm management practices and safety for agricultural workers by providing information regarding precautionary measures. This study will engage oil palm workers in Johor which are tasked to carry out pesticides handling activities. A total of 138 respondents were selected for the study. The methodology approaches that will be used in this study are questionnaire and interview. The results of this study will be used as reference in the farming industry, particularly the awareness and understanding of good farm management practices and safety for agricultural Workers By Informing Them Of A Precautionary Measure.

Generic Escherichia coli contamination of spinach at the preharvest stage: effects of farm management and environmental factors.

The objective of this study was to determine the effects of farm management and environmental factors on preharvest spinach contamination with generic Escherichia coli as an indicator of fecal contamination. A repeated cross-sectional study was conducted by visiting spinach farms up to four times per growing season over a period of 2 years (2010 to 2011). Spinach samples (n = 955) were collected from 12 spinach farms in Colorado and Texas as representative states of the Western and Southwestern United States, respectively. During each farm visit, farmers were surveyed about farm-related management and environmental factors using a questionnaire. Associations between the prevalence of generic E. coli in spinach and farm-related factors were assessed by using a multivariable logistic regression model including random effects for farm and farm visit. Overall, 6.6% of spinach samples were positive for generic E. coli. Significant risk factors for spinach contamination with generic E. coli were the proximity (within 10 miles) of a poultry farm, the use of pond water for irrigation, a >66-day period since the planting of spinach, farming on fields previously used for grazing, the production of hay before spinach planting, and the farm location in the Southwestern United States. Contamination with generic E. coli was significantly reduced with an irrigation lapse time of >5 days as well as by several factors related to field workers, including the use of portable toilets, training to use portable toilets, and the use of hand-washing stations. To our knowledge, this is the first report of an association between field workers' personal hygiene and produce contamination with generic E. coli at the preharvest level. Collectively, our findings support that practice of good personal hygiene and other good farm management practices may reduce produce contamination with generic E. coli at the preharvest level.

Allocative efficiency constraints in snail ( Archachatina marginata ) production by small scale snail farmers in Cross River State, Nigeria

This study examined constraints militating against the profitability potentials of snail (Archachatina marginata) production by small-scale snail farmers in Cross River State, Nigeria. Data were obtained from a random sample of 120 respondents in the study area by means of structured and semi-structured questionnaire. The first stage involved random selection of three (Ogoja, Ikom and Odukpani) local government areas from eighteen local government areas in Cross River State, Nigeria. This was followed by random selection of three villages (Igoli in Ogoja Local Government Area, Alesi in Ikom Local Government Area and Adiabo in Odukpani Local Government Area) in Cross River State. The respondents were randomly selected from each of the villages, 40 respondents were selected each from three villages, making a total number of 120 respondents. Data collected were analyzed using descriptive statistics and costs returns analysis. The results indicated that Cobb-Douglas production function had the best fit in explaining the relationship between output of snail and inputs used, the coefficient of multiple determinant (R2=0.60 indicates that sixty percent of the variability in output of snail is explained by the independent variables). Results from the analysis revealed that the marginal value products of farm size, labour, farm management practices and operating costs were N1080, N20.6, N972.8, N14.84 respectively, there existed allocative inefficiency, there is a high potential for snail farmers to increase their yields and income. Further analysis of results revealed that net returns on snail is N2,935,000.00 with return on every naira invested of N0.14 is also positive indicating a profit from the business, with attractive net return on investment. This study shows that snail farmers are faced with several problems in their production activities. These problems or constraints affect the efficiency of snail production in the study area. Notable among them are high cost of feed supplement, lack of capital, inaccessibility of formal credit source because lack of collaterals, lack of extension agents, lack of medication/vaccines, poor production infrastructures and lack of good farm management practices occupied 15%, 14.17%,11.67%,10%,9.17%,9.17% and 8.33% respectively. The constraints associated with the business as highlighted in this paper if tackled could pave a way to increase profit and this will alleviate poverty in Cross River State. Hence, forefficient production of snail in the study area, these constraints must be drastically reduced to the barest minimum. This can be done through efficient policy formulation and implementation, proper supervision of snail production programme, effective extension services and proper agricultural financing. Snail farmers in the study area should be train by extension agents on how to control some of constraints that militate against the profitability potential of snail production. Beside that snail farmers should form cooperative group (s) in order to obtain loans from bank (s) to increase their capital base for higher output.

Seaweed micropropagation techniques and their potentials: an overview

The seaweed industry worldwide uses 7.5–8.0 million tonnes of wet seaweeds annually with a majority of it derived from cultivated farms, as the demand for seaweed based-products exceeds the supply of seaweed raw material from natural stocks. The main advantage of cultivation is that it not only obviates overexploitation of natural populations but also facilitates the selection of germplasm with desired traits. To enhance the economic prospects of seaweed cultivation, varied practices, such as simple and cost effective cultivation methods, use of select germplasm as seed stock coupled with good farm management practices, etc., are adopted. Nevertheless, in vitro cell culture techniques have also been employed as they facilitate development and propagation of genotypes of commercial importance. There are more than 85 species of seaweeds for which tissue culture aspects have been reported. Although the initial aim of these techniques focuses mostly on genetic improvement and clonal propagation of seaweeds for mariculture, recently the scope of these techniques has been extended for use in bioprocess technology for production of high value chemicals of immense importance in the pharmaceutical and nutraceutical sectors. Recently, there has been a phenomenal interest in intensifying seaweed tissue and cell culture research to maximize the add-on value of seaweed resources. This paper deals with the status of seaweed micropropagation techniques and their applications in the context of the marine biotech industry. Further, it also provides an analysis of the problems to be resolved for removing the barriers that are impeding the true realization of potentials offered by these techniques for sustainable development and utilization of seaweed resources.

Managing emerging diseases borne by fruit bats (flying foxes), with particular reference to henipaviruses and Australian bat lyssavirus.

Since 1994, a number of novel viruses have been described from bats in Australia and Malaysia, particularly from fruit bats belonging to the genus Pteropus (flying foxes), and it is probable that related viruses will be found in other countries across the geographical range of other members of the genus. These viruses include Hendra and Nipah viruses, members of a new genus, Henipaviruses, within the family Paramyxoviridae; Menangle and Tioman viruses, new members of the Rubulavirus genus within the Paramyxoviridae; and Australian bat lyssavirus (ABLV), a member of the Lyssavirus genus in the family Rhabdoviridae. All but Tioman virus are known to be associated with human and/or livestock diseases. The isolation, disease associations and biological properties of the viruses are described, and are used as the basis for developing management strategies for disease prevention or control. These strategies are directed largely at disease minimization through good farm management practices, reducing the potential for exposure to flying foxes, and better disease recognition and diagnosis, and for ABLV specifically, the use of rabies vaccine for pre- and post-exposure prophylaxis. Finally, an intriguing and long-term strategy is that of wildlife immunization through plant-derived vaccination.

Toxins of filamentous fungi.

Mycotoxins are low-molecular-weight secondary metabolites of fungi. The most significant mycotoxins are contaminants of agricultural commodities, foods and feeds. Fungi that produce these toxins do so both prior to harvest and during storage. Although contamination of commodities by toxigenic fungi occurs frequently in areas with a hot and humid climate (i.e. conditions favorable for fungal growth), they can also be found in temperate conditions. Production of mycotoxins is dependent upon the type of producing fungus and environmental conditions such as the substrate, water activity (moisture and relative humidity), duration of exposure to stress conditions and microbial, insect or other animal interactions. Although outbreaks of mycotoxicoses in humans have been documented, several of these have not been well characterized, neither has a direct correlation between the mycotoxin and resulting toxic effect been well established in vivo. Even though the specific modes of action of most of the toxins are not well established, acute and chronic effects in prokaryotic and eukaryotic systems, including humans have been reported. The toxicity of the mycotoxins varies considerably with the toxin, the animal species exposed to it, and the extent of exposure, age and nutritional status. Most of the toxic effects of mycotoxins are limited to specific organs, but several mycotoxins affect many organs. Induction of cancer by some mycotoxins is a major concern as a chronic effect of these toxins. It is nearly impossible to eliminate mycotoxins from the foods and feed in spite of the regulatory efforts at the national and international levels to remove the contaminated commodities. This is because mycotoxins are highly stable compounds, the producing fungi are ubiquitous, and food contamination can occur both before and after harvest. Nevertheless, good farm management practices and adequate storage facilities minimize the toxin contamination problems. Current research is designed to develop natural biocontrol competitive fungi and to enhance host resistance against fungal growth or toxin production. These efforts could prevent toxin formation entirely. Rigorous programs for reducing the risk of human and animal exposure to contaminated foods and feed also include economically feasible and safe detoxification processes and dietary modifications. Although risk assessment has been made for some mycotoxins, additional, systematic epidemological data for human exposure is needed for establishing toxicological parameters for mycotoxins and the safe dose for humans. It is unreasonable to expect complete elimination of the mycotoxin problem. But multiple approaches will be needed to minimize the economic impact of the toxins on the entire agriculture industry and their harmfulness to human and animal health.