Infections farming

Despite the obvious need for accruing more data, our current knowledge indicates that it is highly unlikely that prion infected farm-animal derived foods or products are a significant source of human prion diseases. 

Comments Virus is most likely introduced during or directly after spawning. Infected farms experience losses up to 70%. First reported from Europe, measures of control and prevention have been developed and successfully tested by the Dutch. Most notably, virus spreads by attaching itself to mushroom spores which then become airborne. Virus also spreads through the contact of healthy mycelia with diseased mycelia. Afflicted mushrooms are soon exploited by a host of other parasites, making a late and accurate diagnosis of this contaminant difficult. 

BARKER D E, BRADEN L M, COOMBS M p and BOYCE B (2009) Preliminary studies on the isolation of bacteria from sea Uce, Lepeophthdrus salmonis, infecting farmed salmon in British Columbia, Canada , Parasitol Res, 105,1173-1177. 

Coccidiosis is a widespread disease that occurs most often in fowl, such as chickens and turkeys, and other farm animals (cows, sheep, swine, horses, and rabbits) (11). In chickens the disease has caused severe economic losses. Coccidiosis also occurs in ox, water buffalo, zebu, bighorn sheep, wild goat, alpaca, Hon, puma, fox, mink, parakeet, Canada goose, snow goose, and camel, among others. It is seen only rarely in humans, and dogs and cats are only occasionally infected. 

The nature of the conditions of intensive production, however, can increase the risk of diseases and infections which can spread very rapidly and devastate large numbers of animals." Thus it is common practice for producers of poultry to add coccidiostats to their diets and vaccines to their drinking water in order to prevent coccidiosis and other infectious diseases such as bronchitis and Newcastle disease. A similar problem exists for intensively reared fish, where it is necessary to add antibiotics to their diets. A problem with intensively reared fish is that their diet is added directly into the water in which they live thus drugs and other additives in the diet are relatively easily dispersed into the local environment of fish farms, where they can increase bacterial resistance and also cause problems such as algal blooms. 

Amoebal infections, particularly of farm animals and the female human genitalia, are at best only annoying. All too often the problem encountered leads to difficult diarrheas. A group of nitroimidazoles have activity against the causative organisms and consequently have been widely synthesized. 

Escherichia coli is a cause of enteritis in young infants and the young of farm animals, where it can cause diarrhoea and fatal dehydration. It is a common infectant ofthe urinary tract and bladder in humans, and is a cause of pyelitis, pyelonephritis and cystitis. 

The most satisfactory method for the organic farmer to reduce the risk of infection to lambs from internal parasites is to practise clean grazing, which reduces parasitic infection and increases lamb growth rate (Fig. 3.5). The most effective method of clean grazing is, as we have seen, to use a three year rotational system with sheep, followed by cattle, and then arable. This presupposes land that can be ploughed. On permanent pasture farms with no arable, beef and sheep should be alternated. To make this effective, it helps if there are as many beef livestock units as sheep. If the farm contains only sheep, then it is advisable to alternate on an annual basis between ewes with twins and ewes with singles. If the flock normally produces mostly... 

Rodenburg T.B., Van derHulst-van Arkel, M.C. and KwakkelR.P. (2004). Campylobacter and Salmonella infections on organic broiler farms, Netherlands Journal of Agricultural Science, 52, 101-108. 

Among the studies that have investigated the effect of transport, the prevalence of E. coll 0157 H7 in cattle after transport and outdoor temporary confinement (lairage) did not increase and remained slightly lower than at the farm (Minihan et al., 2003). In a recent report that investigated the effect of transport duration on the prevalence of serotype 0157 in calves that had been fed pasture, Bach et al. (2004) indicated that animals that were transported for approximately 13 hours were more susceptible to infection after arriving... 

Given the diversity of disease-causing organisms, the interactions between farm-specific environmental factors and the types of mastitis causing pathogens found, the potential efficacy of antibiotic treatments can only be assessed accurately in the context of the specific on-farm conditions. Furthermore, many recent investigations concluded that, except for some specific infections caused by streptococci, a prophylactic and or longer-term use of antibiotics for chronic and sub-clinical mastitis should not recommended in the future (Deluyker et al., 2005). 

One of the most important methods of reducing Fusarium infection risk by minimizing inoculum levels is to establish diversified crop rotations which avoid growing maize and cereals before cereals. Since maize as a pre-crop for cereals (especially wheat) is rarely used in organic systems, this risk is applied mainly to conventional farming systems where this practice has increased over the last 20 years. 

Compared to the preventative strategies described above, weed control is thought to have a relatively minor effect on Fusarium infection and mycotoxin levels in grain, but there are few studies available. However, it should be noted that weed density is often higher in organic farming systems and that certain weeds can act as alternative hosts for Fusarium. For example, Fusarium contamination has been detected by Meier (2003) especially on climbing... 

Many grasses are known to act as reservoirs and sources of primary C. purpurea inoculum (Hoffmann and Schmutterer, 1983 Agrios, 1997). Since beetle banks and non-crop field margins are commonly used in organic farming to increase biodiversity, it is possible that these areas may also become sources of Claviceps inoculum. The goal for farmers must be to achieve a balance between the benefits of on-farm biodiversity (e.g. improved habitat for pest predators) and the risk of increased infection by fungi such as Claviceps. 

May require removal and destruction of infected plants. Incineration of impacted fields may be required. Consult local/state agricultural assistance office. Many fungi are easily spread by mechanical vectors (e.g., farm implements, track out, running water) and extreme care must be taken to avoid further contamination. Wear disposable protective coverall, disposable boot covers, and disposable gloves. Insects may also act as mechanical vectors for some plant fungi and, if appropriate, response activities must also include efforts to contain and eliminate these vectors. 

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