|FACE TO FACE
|Year : 2015 | Volume
| Issue : 2 | Page : 139-141
An E-mail interview with Prof. Jeremy S. Gray
|Date of Web Publication||10-Aug-2015|
|How to cite this article:|
. An E-mail interview with Prof. Jeremy S. Gray. Trop Parasitol 2015;5:139-41
Tropical Parasitology (TP): As an eminent expert member of various organizations, please share your views and research experiences in parasitology in context to tick-borne diseases.
Prof. Jeremy Gray: My interests and activities in ticks and tick-borne diseases date from 1974 when I accepted a lecturing post at University College Dublin and started work on the ecology of Ixodes ricinus and the epidemiology of bovine babesiosis. In the years that followed Lyme borreliosis became a topic of major interest in North America and Europe. This interest resulted in the establishment in 1993 of a European Union Concerted Action (EUCALB), which I co-ordinated. In 2011, the group of scientists and physicians in EUCALB formed a study group, ESGBOR, under the umbrella of the European Society of Microbiology and Infectious Disease. During my research career, I have seen research emphasis switch from ecology and experimental biology to molecular biology, which to a large extent now drives both diagnostics and ecology. In some respects, this has been to the detriment of the subject, since it appears to be much easier to obtain grants that concentrate on the development of new technologies than those that try to focus on practical preventive measures.
Furthermore, it is now only too easy to accumulate data on the detection of pathogens in ticks without the provision of any biological insights or meaningful conclusions. Many papers are simply lists of pathogens presented in the name of "risk."
TP: Babesia sp. is believed to be an emerging parasite currently. What could be the possible reasons for such emergence?
Prof. Jeremy Gray: The main reason for emergence of these parasites in human medicine is a vastly increased awareness, fuelled largely by the American experience with Lyme borreliosis, which has led to increased interest in concurrent infections including Babesia microti. A secondary factor is the rapid development of accessible technology for the detection of parasites in both patients and vector ticks. Lastly, in Europe and North America, the population of immunosuppressed patients has grown for various reasons and this may have led to an increased prevalence of cases.
TP: Many reports on co-infection with other parasites and bacteria are coming up. How much is the significance of these co-infections and what may be the possible factors influencing them?
Prof. Jeremy Gray: The major driver for the study of co-infections is that in the USA, which experiences the highest incidence of human babesiosis, the vector tick Ixodes scapularis, transmits B. microti, Borrelia burgdorferi and Anaplasma phagocytophilum, all of which can cause disease in their own right. In Europe, another tick species, I. ricinus transmits even more pathogens to humans and in addition to those above, transmits Babesia divergens, Babesia venatorum, several genospecies of Borrelia and tick-borne-encephalitis virus. However, in contrast to the USA, co-infections in patients are relatively rarely reported, apart perhaps from Lyme borreliosis and tick-borne encephalitis.
TP: Vector-borne infections have been a global problem for many decades. As you have contributed immensely in the research on vectors transmitting Babesia sp and other related pathogens, what is the importance of the role of detection of such organisms in these vectors and prevention of transmission?
Prof. Jeremy Gray: My comments under question 1 are also relevant here. Of course, it is important to know what pathogens are present in the tick population, but it is just as, if not more, important to have good surveillance and diagnostics for the detection of actual disease. The sensitivity and specificity of molecular detection tends to generate lists of pathogens that have only loosely been assigned to a disease. It is therefore important to have a clear idea wherever possible of relevant pathotypes. A good example of this is B. microti, in which the vast majority of strains are nonpathogenic so that their detection in ticks is of limited significance in relation to human disease unless the strain has been well characterized. On the other hand, the detection of Borrelia myamotoi led directly to the detection of a previously unsuspected disease associated with this organism, but such pathogen detection-led epidemiology is relatively rare.
TP: Can the current research on tick-borne diseases shed any light on research on Babesia sp?
Prof. Jeremy Gray: Much of my previous responses are relevant here as well. Most of the approaches to tick-borne diseases in general also apply to Babesia spp, particularly in the associating the significance of prevalence in ticks to the epidemiology of the disease. Where babesiosis might be a special case is first in the threat that some species pose to the blood transfusion service and second, in the precise way that immunodeficiencies lead to acute infections as caused by some species of Babesia such as B. divergens.
TP: What is the current status regarding the diagnosis of babesiosis and its newer methods?
Prof. Jeremy Gray: Diagnosis in human patients is strongly dependent on the clinical presentation and on the detection of parasites by light microscopy. In the acute form, occurring particularly in B. divergens- infected asplenic patients, the manifestations are fever, hemoglobinuria, acute anemia and jaundice. The chronic form associated with B. microti is more difficult to diagnose because the presentation resembles that of many other infectious diseases. The fever is mild and is usually accompanied by chills and sweats, chronic anemia, malaise and myalgia. Using light microscopy, babesiosis can be differentiated from malaria because infected erythrocytes do not contain hemozoin. In the case of B. divergens - type infections divergent paired pyriforms are diagnostic.
Tetrads (four pyriforms attached to each other) occur in both B. divergens and B. microti infections but are not common and ring forms are usually predominant in the latter.
PCR should also be used and can differentiate different species, which may be important for the choice of antimicrobials since B. divergens and B. microti - type parasites differ in their susceptibilities. Serology, mainly immunofluorescence, is of little use in acute infections but is relevant to chronic infections caused by B. microti.
TP: Can you throw some light on the epidemiology of Babesia sp. and the distribution of the various species in your region?
Prof. Jeremy Gray: In Europe the main cause of human babesiosis is B. divergens, which occurs in cattle, causing a disease colloquially known as redwater fever, and transmitted by the tick, I. ricinus. The vast majority of patients have been asplenic, often with other immunocompromising conditions such as Hodgkin's lymphoma. The incidence in cattle appears to be declining throughout Europe, but there appear to be an increasing number of published reports. There is some evidence that similar parasites occur in red deer but their zoonotic status is unknown. A related parasite, B. venatorum, has been implicated in three cases. It is transmitted by the same vector and the reservoir host has been established as roe deer (Capreolus capreolus). The fact that several cases have emerged in China, where there are no roe deer, suggests that other deer species are involved. Despite the fact that I. ricinus also tranmits B. microti and is commonly infected with strains of this parasite, there has only been one authenticated endemic case, suggesting that most strains are nonpathogenic in humans.
TP: Are there any international bodies looking into research on such tick-borne diseases?
Prof. Jeremy Gray: I have referred to EUCALB and ESGBOR above (question 1). These networks focus on Lyme borreliosis, but also consider babesiosis and tick-borne encephalitis. Another network, ESCCAR, also based in Europe, focuses on rickettsial infections. Another organization, Scandtick, seeks to promote research in Norway, Sweden, Finland, and Denmark. None of these organizations are a source of funding. There are many national networks but I am not aware of any scientifically-based international bodies that specifically fund or focus on ticks and tick-borne diseases.
TP: Vector control is a very important part in tackling infections of many diseases. How much successful is the vector control program in the developed countries? Kindly throw some light on the status in developing countries.
Prof. Jeremy Gray: I regret that this topic is far too big to discuss here in detail. However, in short, there is little evidence that there has been any useful control of vectors transmitting zoonotic tick-borne diseases since large scale spraying of vegetation with toxic chemicals in the Soviet Union ceased in the 1970s. In contrast, there has been intense interest and activity in vector control in relation to livestock for many decades. The application of acaricides remains the main means of control here, but there are substantial environmental and resistance problems. Some progress has been made in the deployment of tick-resistant cattle and of vaccines targeting a handful of tick species but mainly in relatively developed countries such as Australia and Argentina.
TP: Kindly share few suggestions for the budding scientists in the field of parasitology.
Prof. Jeremy Gray: It is clear that to be an effective modern scientist in this field of research it is necessary to acquire good skills in molecular biology. However, this has often been to the detriment of knowledge about the actual organisms themselves (ticks and pathogens) and the habitat in which they are found. This can result in research data without a useful context. Scientists need to have a good grasp of what molecular tools can do, but very importantly also what they can contribute to risk assessment and the subsequent implementation of control measures.
One final point - I urge young scientists to publish their findings and when they do, make sure that the paper is written in good scientific English. Many papers are rejected because the reviewers find it difficult to be objective about the science when struggling to understand what has been written. For authors whose native language is not English this may mean making use of professional scientific editing services, which is an expense. Consequently, it is vital that for any research project the costs should include funds for communication.
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