Parasites are those organisms which exist in abundant form on our planet earth. They have complex kind of diversity. These are the parasites, through which the communities are interconnected.
They have great impact on eating habits, our environment, behavior, and most important factor is interaction among the communities. Parasites influence the sustainability among the species like invertebrates, birds, fish and mammals.
They also influence the food security, its quality and availability of food for mankind. Parasites have role in transmission of zoonotic diseases, so they influence the human health, food security and biodiversity.
Zoonotic diseases are higher in those areas where climate is temperate, because the inhabitants of those areas rely on wildlife species for their food, so they are at greater risk for zoonosis.
The species of parasites which originate from these areas or new species which are getting discovered day by day, are entirely different from those which exist in tropical or subtropical areas, means climate has major impact on their biodiversity.
People who work in biosecurity labs they are at greater risk for any kind of disease transmission, those people includes biologists, lab technicians, fish farmers, public health workers, local health communities and wildlife workers (people who work with wild animals). Like we all know that, parasites are the most integral part of all ecosystems.
They have a unique feature that they have both kind of hosts vertebrates and invertebrates. That’s I am trying to enlighten your thoughts about these complex and diverse creatures. Major parasite groups are Platyhelminthes, nemathelminths, protozoa and insects.
They have complex life cycles and exhibit various forms which are not present in other pathogenic organisms. If you look around there is not a single soul on planet earth which never got infected by these organisms. They are entirely distributed around the globe. Some of the researchers mentioned that in a single fish, it has been observed that she got over 100 parasites in no time.
They are present in terrestrial and aquatic both ecosystems. These creatures have evolved them selves according to evolution and their environment. There are thousands of research papers indicating that, parasites are evolving day by day. We are observing various parameters like infectivity, resistance, tolerance and complexity.
These complex organisms cause disease in individuals and leading to morbidity and sometimes mortality. They have influences upon population dynamics. They also have competition among themselves. As I mentioned earlier that they have complex life cycles, some of the parasites exhibit direct and some have indirect life cycles.
These organisms have various requirements and sometimes without resources they cannot thrive, like temperature, humidity, salinity, light and type of host. Like in arctic few species thrive there, which have evolved them selves according to their ecosystem. Parasite population also get influenced by availability of host.
Ultimately, we are able to say that, the parasite life cycles and parasitic disease transmission are directly influenced through changes in population of both predator and prey species.
Indirect life cycles are complex, they involve sometime vectors as their intermediate hosts, in these vectors there are various type of flies, like biting and sucking flies, ticks, mites and other arthropods.
These vectors play major role in transmission of these creatures (Parasites) among terrestrial and aquatic living beings. Parasites basically give indication about the ecological structure of an area according to their way of survival. There are diverse assemblies of parasites and this indicates the health of an ecosystem.
The parasites present in an area are indicative of ecosystem stability, because there are interactions between birds, mammals and aquatic wildlife so it forms the food web and parasites got dispersed through this way. So, such relationships of these animals reflect the parasite diversity.
Here I am going to mention some of wild bird species which transmit parasites by migration and it’s the most important thing that as they travel on seasonal changes and distribute parasite in all those areas where they stay.
Some important bird species are (Passer iliaca, P. domesticus and Melospiza; the cocoa, wood, clay colored, forest, bare eyed and red legged thrushes (Turdus fumigatus, Hylocichla mustelina, T. grayi, T. lherminieri, T. nudigenis and T. plumbeus);
The American robin (T. migratorius); the Baltimore oriole (Icterus galbula); the reddish winged bare eye (Phlegopsis erythroptera); the rufous-tailed ant-wren (Epinecrophylla erythrura); the common yellowthroat (Geothlypis trichas);
The bananaquit (Coereba flaveola); the black throated blue warbler (Setophaga caerulescens); the dark-eyed junco (Junco hyemalis); the red eyed vireo (Vireo olivaceus); the northern mockingbird (Mimus polyglottos); and the worm eating black & white warblers (Helmitheros vermivorus and Mniotilta varia).
So, all these birds migrate and transmit parasites so ultimately there is interaction between parasites of both areas and in future there will be more complexity, we are heading towards our own destruction. Steps must be taken that not to disturb nature, we like to play with nature, when it will play with us, it would be really lethal.
Authors: Hammad Ur Rehman Bajwaa,*, Muhammad Kasib Khana, Muhammad Rashid Khalid Bajwab, Muhammad Shafi Hasnia, Nauman Iftikhara, Gulfam Younusc
- Department of Parasitology
- Department of CMS
- Institute of Animal and Dairy Sciences
University of Agriculture, Faisalabad-38040 Pakistan