Human health and modern agriculture are inextricably linked. As a result, the field of agricultural health emerged over the past decades to understand the impact of agricultural management on human beings. Agricultural health is the study of environmental, occupational, dietary, and genetic factors on the health of farmers, farm families, pesticide applicators, and others who work with and are exposed to agricultural chemicals. Especially recent seed and fertilizer innovations may lead to negative effects on the physical and mental well-being of farmers, farm workers etc. (NIH 2013). Agriculture in developing countries is specifically subject to problems related to food safety, which emerges from diseases spread by animals to farmers or by poor use of pesticided. The International Livestock Research Institute has pointed out the risks for human health derived from food safety concerns (ILRI 2013).
Zoonoses - Diseases that animals pass to humans
Zoonoses are diseases that animals pass to humans. Micro-organisms such as bacteria, fungi, parasites and viruses can cause illness by infecting the body when they are breathed in, swallowed, or when they penetrate the skin through small cuts or grazes.
Common zoonoses include:
- orf from sheep or goats, which produces painful pustules on hands, arms and the face;
- leptospirosis from rats (Weil’s disease) and cattle urine, which causes a feverish illness with headache and can result in meningitis. Early treatment is vital;
- ringworm, which is a fungal disease from many types of livestock;
- enzootic abortion (chlamydia psittaci) from sheep. Pregnant women should not associate or work with ewes during lambing, nor be exposed to soiled clothing contaminated with afterbirths etc as severe illness and miscarriage may result;
- cryptosporidiosis, from a parasite picked up by touching livestock, animal housing, or feed, which can cause diarrhoea in humans, and be particularly severe in young children;
- Lyme disease, from the bite of an infected tick in woodland or grassland. Starts with a rash around the site of the bite and intermittent flu-like symptoms. More serious symptoms affecting the nervous system may develop later. Early diagnosis is essential;
- Q fever from cattle and sheep can also be carried by other mammals, including deer. Leads to acute illness with feverish symptoms but occasionally pneumonia and other complications. There is also a more serious chronic form of Q fever;
- ornithosis (another form of chlamydia psittaci) from birds, which can cause flu-like symptoms in humans, followed by pneumonia (HSE 2013).
Fertilizer use impacts on human health
Another issue of concern is the potential negative impact of fertilizer use on human health. For example, For decades, nitrate in drinking water has been a concern. While new evidence shows a positive role for nitrate in cardiovascular health, and the occurrence of methemoglobinemia has been rare in developed countries, questions remain regarding its potential relation to carcinogenic nitrosamines. More recent questions have arisen as to whether ammonia emissions from fertilizer could contribute to the formation of unhealthy levels of smog.Eutrophication leading to harmful algal blooms has been attributed in many places to losses of agricultural nutrients (IPNI 2011).
HSE. 2013. Zoonoses. Available online: http://www.hse.gov.uk/biosafety/diseases/zoonoses.htm (accessed 14-11-13).
ILRI. 2013. Food safety and zoonoses programme. Available online: http://cgspace.cgiar.org/bitstream/handle/10568/33798/foodsafety_zoonoses_profile.pdf?sequence=1 (accessed 14-11-13).
IPNI. 2011. Fertilizer use and human health. Available online: http://www.ipni.net/ipniweb/pnt.nsf/5a4b8be72a35cd46852568d9001a18da/55b4ba60b0e1b00d85257846005b5fd6!OpenDocument (accessed 14-11-13).
NIH. 2013. Agriculture and health. Available online: http://www.niehs.nih.gov/health/topics/population/agricultural/ (accessed 14-11-13).