Parasitism and ecological parasitology

Parasitism as one of the life modes is a general biological phenomenon and is a characteristic of all viruses, many taxa of bacteria, fungi, protists, metaphytes, and metazoans. Zooparasitology is focused on studies of parasitic animals, particularly, on their taxonomy, anatomy, life cycles, host-parasite relations, biocoenotic connections, and evolution. Ecological parasitology is a component of ecology, as the scientific study of the relation of living organisms with each other and their surroundings. In the present paper, critical analysis of the problems, main postulates, and terminology of the modern ecological parasitology is given.     

Parasites, parasitology and parasitologists

The science of parasitology is one of the many new disciplines of the twentieth century, as such it is a dynamic and rapidly evolving science which encompasses an increasing number of sub-disciplines and technologies. However, will the fragmentation involved in current methods of scientific enquiry and the competition for funding mean the decline of certain areas of parasitology or perhaps the complete loss of the discipline. This paper attempts to address these questions by considering the development of the discipline of parasitology especially within Australia and by considering the mechanisms of attaining funding for science. Technological change and its impact on parasitology is also considered, and requirements for maintenance of the discipline and its practitioners are suggested.     

ParaSite: The Pick of Parasites on the Web

While a steady flow of questions were put to the general parasitology newsgroup during November, none provoked discussion. Other discussion lists came to life:     

Are ChatGPT and other pretrained language models good parasitologists?

Large language models, such as ChatGPT, will have far-reaching impacts on parasitology, including on students. Authentic experiences gained during students’ training are absent from these models. This is not a weakness of the models but rather an opportunity benefiting parasitology at large.     

Pulse radiolysis, free radicals and antiparasitic drugs

Free radicals have been proposed to be of significance in several important aspects of parasitology because of their generation during parasitic infection and chemotherapy, and their potential for causing cellular damage. Roger Bisby describes how radiation chemical methods, and pulse radiolysis in particular, may be used to generate and study free radicals that are of interest in parasitology.     

Significance of ixodid tick (Parasitiformes,Ixodidae) population structure for maintenance of natural foci of infection

Basic postulates of the theory of natural focality of infections are considered in terms of modern ecological parasitology using the example of Ixodes ricinus and I. persulcatus ticks, the main vectors of tickborne encephalitis and borrelioses in Eurasia. Consideration is given to data on the population structure of ticks, their distribution in ecosystems, abundance, mortality at different stages of the life cycle, seasonal dynamics of activity, occurrence on different vertebrate species, relationships with potential hosts, and connections agents of infections. Due to long individual life span and development of one generation over 3–6 years, tick vector provide not only for transmission of pathogens, but also for their long-term storage and amplification. Several alternative routes of tick infection of ticks provide for pathogen exchange between individuals at different phases of development within one generation and between feeding ticks of different generations.     

Current bioethical issues in parasitology

Parasitic diseases constitute the most common infections among the poorest billion people, entailing high mortality rates and leading to long-term infirmities and poverty. Although the setting-up of public health programs implies many ethical consequences, the range of specific questions in parasitology that can be attributed to bioethics remains, to a large extent, unexplored. From the present analysis, it emerged three main issues which characterize ethical stakes in parasitology: accounting the complexity of the field of intervention, putting the principle of justice into practice and managing the changing context of research. From the research angle, medical parasitology-mycology, as other biological disciplines, is undergoing tensions derived from biological reductionism. Thanks to its links with the history and philosophy of the sciences, bioethics can help to clarify them and to explain the growing hold that technologies have over scientific thinking. On the whole, researchers as well as clinicians are called on to assume a specific responsibility, proportional to their competence and their place in the making of scientific, health, economic and social decisions.     

Online searching of parasitology literature

To keep abreast of the expanding literature on parasitology is virtually a such full-time pursuit of source literature becomes impossible with other commitments, encouraging recourse to secondary sources such as abstracting journals, Current Contents, and even Parasitology Today. Another approach - increasingly used since its faltering introduction in the 1970s- involves online searching of computerized databases. Here, John Eyers and Angela Taylor review the application of such systems to parasitology.     

Status of medical parasitology in South Africa: new challenges and missed opportunities

In South Africa medical parasitology is neglected due to a shift in funding priorities to focus on HIV, tuberculosis and malaria. Evidence suggests that helminth infections have deleterious effects on HIV and tuberculosis. A multisectoral approach involving key government and research institutions is required to rekindle interest in medical parasitology.     

The isolation of nucleic acid from nematodes requires an understanding of the parasite and its cuticular structure

As parasitology increasingly becomes the domain of molecular biologists, it is important to keep in mind that a fundamental understanding of the whole parasite, its structure and behaviour can help to solve complex problems of molecular biology. Hugh Dawkins and Terence Spencer discuss the preparation of DNA from filaform larvae of Trichostrongylus colubriformis and Ostertagia circumcincta and how a detailed knowledge of the morphology and life cycle of each parasite helps in this process.     

Of lice and men: The return of the ’comparative parasitology‘ debate

The question of whether or not parasite phylogeny provides information about host relationships (‘comparative parasitology’) reached a peak in 1957 in a vigorous debate between Gunther Timmermann and Ernst Mayr. Timmermann argued that parasites were associated with their hosts by descent and that this produced congruent host and parasite phylogenies. In contrast, Mayr argued that parasites were often associated by colonization and that this led to incongruence between host and parasite phylogenies. To test these differing views. Adrian Paterson, Russell Gray and Graham Wallis derived a procellaniform phylogeny. This tree is here compared with Timmermann's tree based on the relationships of feather lice. Timmermann's tree is more similar to the seabird phylogeny than would be expected by chance. Thus, support is found for the ‘comparative parasitology’ approach.     

Disease mapping in veterinary parasitology: an update

The development of methods for disease mapping has progressed considerably in recent years. Geographical Information Systems (GIS) and Remote Sensing (RS) represent new tools for the study of epidemiology, and their application to veterinary medicine, and in particular to veterinary parasitology, has become more and more advanced to study the spatial and temporal patterns of diseases. The present paper reports an update regarding the use of these technologies in veterinary parasitology.     

Marine parasites: an Australian perspective

A review is given of major studies in marine parasitology in Australia. Aspects discussed include: geographical distribution of parasites in Australian coastal waters and their affinities to parasites of other zoogeographical regions; species diversity in Australian coastal surface and deep waters; use of marine parasites for stock discrimination; use of marine parasites as ecological models; ultrastructural and phylogenetic studies of marine parasites; and effects of marine parasites on their hosts.     

Parasite systematics in the 21st century: opportunities and obstacles

Thanks to the phylogenetic systematics revolution, systematic parasitology is poised to make significant contributions in tropical medicine and public health, biodiversity science, and evolutionary biology. At the same time, the taxonomic impediment is acute within parasitology. Both systematists and non-systematists must be interested in working towards common goals and establishing collaborative efforts in order to re-vitalize and re-populate systematic parasitology.     

Collaborative parasitology: student partnerships in open education

Student-faculty partnerships can drive innovation in parasitology education and outreach. We provide recommendations for building successful partnerships during the design, implementation, and impact assessment stages. We also introduce a new series of freely available educational and community outreach materials available on a platform that the parasitology community can contribute to.     

Facts from feces revisited

Obtaining information on wild mammal populations has been a long-standing logistical problem. However, an array of non-invasive techniques is available, including recently developed molecular genetic techniques for the analysis of feces (molecular scatology). A battery of non-invasive, molecular approaches can be used on feces, which in conjunction with conventional analysis are potentially useful for assesing genetic structure, demography and life history of mammals. Several technical problems reman before large-scale studies of feces can be undertaken productively, but already studies are providing insight into population subdivision, food habits, reproduction, sex ratio and parasitology of free-ranging populations.     

Parasites of the superorganism: are they indicators of ecosystem health?

The concept of ecosystem health is derived from analogies with human health, which subsequently leads to the implication that the ecosystem has organismal properties, a 'superorganism' in the Clementsian sense. Its application and usefulness has been the subject of a contentious debate; yet, the term 'ecosystem health' has captured the public's imagination and woven its way into the current lexicon, even incorporated into public policy. However, the application of parasites as bioindicators of ecosystem health poses a curious conundrum. Perceptions of parasites range from mild distaste to sheer disgust among the general public, the media, environmental managers and non-parasitologists in the scientific community. Nevertheless, the biological nature of parasitism incorporates natural characteristics that are informative and useful for environmental management. The helminths in particular have evolved elegant means to ensure their transmission, often relying on complex life cycle interactions that include a variety of invertebrate and vertebrate hosts. The assemblage of these diverse parasites within a host organism potentially reflect that host's trophic position within the food web as well as the presence in the ecosystem of any other organisms that participate in the various parasite life cycles. Perturbations in ecosystem structure and function that affect food web topology will also impact upon parasite transmission, thus affecting parasite species abundance and composition. As such, parasite populations and communities are useful indicators of environmental stress, food web structure and biodiversity. In addition, there may be useful other means to utilise parasitic organisms based on their biology and life histories such as suites or guilds that may be effective bioindicators of particular forms of environmental degradation. The challenge for parasitology is to convince resource managers and fellow scientists that parasites are a natural part of all ecosystems, each species being a potentially useful information unit, and that healthy ecosystems have healthy parasites.     

Parasitoses and development: malaria and echinococcosis]

After having placed emphasis on the cyclic oscillations characterizing the interest of the scientific and political world for parasitology, the author analyzes the various standpoints from which parasitic diseases, and above all malaria, have been dealt with ever since the beginning of this century. Specific criticism is addressed to the military model, which has provided the basis for many eradication campaigns. The author also analyzes the "vicious circle theory", which labelled the activity of the WHO in its first decade of life, and which assumed that breaking the disease and underdevelopment circle was possible by acting mainly or even exclusively on endemic and debilitating diseases. Both these models were tested with success in Sardinia with the 1947-49 antimalaria campaign. However, socio-economic development of the island did not occur as expected, and attempts to export the same approaches to other parts of the world soon disclosed their limitations, leading to major failures. The experience on the fight against echinococcosis is subsequently examined. The conclusions drawn are that many successes may be obtained through a systemic rather than a sectorial approach; and that a "conflicting cohabitation" with diseases is foreseen as a long-lasting reality, and must thus be controlled with the appropriate means.