Impact of Parasites on Food Security

Nowadays, everyone’s agenda is “Food Security”. Food security is a broader term, but it can be defined as “The production of abundant quantity of economical and good quality food that supports the health and welfare of human being throughout the world”.

Impact of Parasites on Food Security

Food security has very clear and important objectives which include elimination of poverty, ensure environmental sustainability and global development. Food production from livestock sector has less negative impact on environment than agriculture sector because agriculture sector plays major role in climate change in term of greenhouse gases.

But health of livestock is very important to get proper production. It can be achieved with the help of good management, nutrition, proper vaccination, breeding program and bio-security. In case of negligence, there is high risk of parasitic infestation.

These parasites cause diseases of gastro-intestinal tract, respiratory system and skin which have negative impact on feed intake, growth rate, fertility, milk yield, carcass weight, carcass composition and wool growth.

Livestock diseases were ranked on the basis of impact on poor people.  Four parasitic diseases fell into 1-10 top most important diseases in which GIT Helminthes fell on 1st, Ectoparasites on 4th, Liver Fluke on 6th and Toxocara vitulorum on 10th position.

Technology and Rural Development are the basic components of Food Security and almost have equal importance. If industry does not adapt the technology, then food security will not be achieved. Similarly, Knowledge, Vaccination, Diagnostic Techniques, disease control and prevention programs require to reach the target population timely and in the proper formats for rural development.

WormBoss” is one of the best examples of rural development that exists at present time. Main focus of WormBoss is to decrease unwanted drenching and to reduce drench resistance when animal production is increasing.

An important existing period of veterinary parasitology was explanation of epidemiology and clarification of pathogenesis of different parasite species such as Fasciola hepatica, Ostertagia ostertagi, Dictyocaulus viviparous and Teladorsagia circumcinta.

Due to rise in quantitative epidemiology, studies on relation between parasites and their hosts increased, and statistical data help in proper understanding of impact of parasitic diseases worldwide.

Research achievements on some important parasites and parasitic diseases supported the food production in the past and will make sure food security in the future. It can be achieved by adaptation of vaccination and disease control program and by the advancement of diagnostic techniques.

Anthelmintic resistance is currently a big issue worldwide. Resistance develops due to under dosage of drug, overuse of Anthemintics and absence of new drugs. Food security cannot be achieved in the absence of new Anthelmintics and its registration.

Prevalence of Ostertagia ostertagi in cattle and Teladorsagia circumcinta in sheep is high in temperate regions. These parasites cause loss of appetite and hypoprotenimia which ultimately result in abomasal tissue damage and loss of production.

Some trematode species such as Fasciola hepatica (Liver Fluke) and Fasciola gigantica cause acute, sub-acute and chronic form of diseases in sheep and cattle, and prevalence of these parasites is high in temperate and tropical regions respectively.

Manifestation of both parasites leads to decrease growth rate, low milk production and infertility. Liver fluke is most common cause of liver condemnation in slaughter houses, therefore it is clearly against the food security agenda in terms of reducing waste.

Duration of pre-patent period of liver fluke is long therefore diagnosis of liver fluke in the live animal has different problems resulting in damage to productivity before the detection of liver fluke’s eggs in feces.

Vaccination against fluke infestation of cattle and sheep is very necessary but it has some problems such as deficiency of naturally acquired immunity in both species, rise of infection through intermediary species and wildlife also play a major role in maintenance of infection in these species.

But transmission of fluke can be reduced via vaccination, resulting in decreased egg production and pasture contamination over a few seasons. There is an additional benefit of vaccination of livestock that is reduction in zoonotic risk of F. hepatica to human, particularly in those countries where human diet contains aquatic vegetation.

Some interesting studies show that F. hepatica produces anti-inflammatory condition in its host, and host becomes susceptible to other pathogens like Salmonella dublin and Clostridium sp. Bacterial infections also have negative impact on growth rate, milk production and fertility.

Poor reproductive efficiency is one of the most important limitations to balanced food production. Abortion and infertility are common in ruminants due to improper breeding, poor nutrition and infectious diseases.

Toxoplasmosis in sheep and Neosporosis in cattle are most important protozoal causes of reproductive disease. Toxoplasma gondii causes abortion in sheep and it also causes zoonotic infecton in human via ingestion of under-cooked meat containing tissue cysts.

Neospora caninum is one of the most significant causes of bovine abortion globally. It causes direct economic losses by loss of pregnancy, notable loss of production in dairy and beef sector, and  the costs of test and cull program.

Parasitologists have contributed to Food Security before the term was originated. Work of parasitologists based on description of life cycle and epidemiology of parasites and their relation with various hosts.

After the discovery of levamisole, benzimidazoles and macro-cyclic lactones, it could be declared that livestock helminthology became a “Cinderella” subject.

Different research councils in the world such as Biotechnology and Biological Science Research Council (BBSRC) and Research Councils UK (RCUK) have decided to work together on Global Food Security initiative. Horizon 2020, a research and revolution program of European Union completely focus on Food Security, Bio-economy and sustainable Agriculture.

Progress on vaccination against parasites in livestock showed that veterinary parasitologists potentially lead the discipline in term of Food Security. Parasitologists are also contributing in development of vaccine against human parasitic diseases including Malaria, Hook Worm and Sleeping Sickness.

In conclusion, future of Veterinary Parasitology and Parasitologists is bright but important thing is that, how to describe to educated population about recent contributions of parasitological research in Global Food Security. This may depend upon parasitologists, how they explain the results of their research and translate into a language that brings proper understanding and impression for those who want to ensure food security in future.

By Dr. Hammad Ur Rehman Bajwa

PhD Scholar, Department of Pathobiology, University of Illinois, Urnana-Champaign.