Hi Everyone, In addition to my project on biting flies impact on feeder cattle, my tutor is a Trypanosoma specialist and he work on several others projects. Thus, last week I had an amazing opportunity because I worked with him in one of these. Indeed, during three days we went in Kachanaburi Province to study the different interaction between the wildlife and the livestock in particular on the parasite transmission between livestock and wildlife. To do that, we went in an elephant farm in the middle of several reserves where some Trypanosoma cases were suspected. In this last blogpost I will treat Trypanosoma, a blood parasite, an usual transmitted thanks to biting flies which are the principal vector. There are many different species of Trypanosoma which can infect animal or human everywhere in the world, but in our case, the study is about Trypanosome evansi, mostly transmitted by Stomoxys and Tabanids and the origin of surra disease [1]. Trypanosome evansi is an extracellular blood parasite. Thanks to it antigenic variation in it surface , it can skirt the immunity system of it host. This antigenic variation allow a chronic induction of the surra disease in the host. Trypanosome evansi is also able to do an immunodeficiency in their host, causing and acute form of surra which could be fatal [2]. In it chronic form, surra cause a lose of weight, growth late, a productivity fall, anemia and sometimes many abortion. These symptom are not too important so farmer don't look for Trypanosoma and the animals are not treated. In is fatal form, surra cause anemia, immunodeficiency and can reach to the nervous system [3]. You have to know that the Trypanosome evansi it's the most spread since we can find it in North Africa, Asia, Europe and Latin America. Even if some humans cases are found in India [4], this species of Trypanosoma have only animal reservoir as cattle, buffalo, pork, horse, camel, dog andalso elephant.[2](thèse) With this high number of animals reservoirs this parasite it's an big issue for wild life because cattle can transmit it to wild animals thanks to insects vectors. Indeed, biting flies are the principal vector to transmit Trypanosoma evansi, in particular Tabanids because of the huge blood quantity they can ingested. Thus, because of the pain caused by their bites Tabanids are hunted by mammals' defensive movement and they have to finish their meal on an other animal. This meal in to time is the principal cause of the transmission of Trypanosoma. In the same way, Stomoxys can also transmit parasites but the risks are lower because of the lower blood quantity ingested. When one case is suspected, it's important to know quickly if it is infected by the parasite. So, in elephant farm and in our cattle farm we did some blood analyses to know if Trypanosoma evansi is present in the herd.
We did the diagnostic in 3 steps : control the hematocrit (to see if the animal are in anemia), observe if there were the hematoparasites with microscope and look for Trypanosoma thanks to Elisa and PCR.
It's the end of my really interesting intership and journey in Thailand. Moreover my project of impact of biting flies on feeder cattle, I discovered an incredible country with a really different culture. It was a great experience and if you have some question about my work, the wildlife project, the life in Thailand or if you need any advices for a trip in this amazing country, I will be really happy to answer you. See you soon in Paris ! Adèle References : [1] Marc Desquesnes, Philippe Holzmuller, De-Hua Lai and all. 2013. Trypanosoma evansi and Surra: A Review and Perspectives on Origin, History, Distribution, Taxonomy, Morphology, Hosts, and Pathogenic Effects. BioMed Research International,Volume 2013. [2] Arthur Kocher, directeur de thèse : Philippe Jacquiet. 2013 La trypanosomose à Trypanosoma evansi chez les chevaux en Thaïlande : enquête épidémiologique et standardisation d’un test ELISA indirect. Université de Toulouse [3] Antoine Moussiaux N., Desmecht D., 2008. Epidémiologie de l’infection par Trypanosoma evansi. Ann. Méd. Vét., 152, 191-201 [4] Joshi PP, Shegokar VR and all. 2005. Human trypanosomiasis caused by Trypanosoma evansi in India: the first case report. Am J Trop Med Hyg 73(3): 491-5 [5] Sow A, Sidibe I, Desquesnes M, Bengaly Z, Pangui LJ. 2006. The application of PCR-ELISA to the detection of Trypanosoma congolense type savannah (TCS) in bovine blood samples. Tropical biomedicine 23:123-129.
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Hello Hello everyone !
It's my last month in Thailand and I have a lot of think to do ! First let me do a short resume of my work until today : during two months I worked in a feeder cattle farm where I learnt a lot about animal behaviour against biting-flies, insect distribution in function of the weather and about different trapping techniques. Now, I am able to identify more of 10 kind of different biting fly and I manipulate the feeder cattle without stress. Here I am In total autonomy because I manage the project alone with Flukes, a Thai Master student and It's a real opportunity to do some stuff which look like borrowed but could be really useful for the future and really interesting for now. Indeed like I am alone in Kampheang Sean I have to communicate (sometime an email it's not enough) about the project with the team and I am going to explain you what I have to do for that. At the beginning the project should end with the end of my internship but we want more data so my tutor decided to continue it until January. But the project take some space in the farm and we need some permission. Indeed, this experiment depend of the Animal Science Department and the Entomology Department so for each of these we have to justify this prolongation. So my first work is to write a short paper of 2 or 3 pages to explain our result and show why we have to continue the project for 2 months more. This is a good exercise to synthesize our project and our result. Then, in three weeks I have to present all the result to the rest of the team. So I have to do a Power point presentation ( In English of course) and do something like a defence in front of many research. I think It's a real opportunity to train me for our final presentation but I am really stressed . If you have some advice for the d-day I would be very happy to heard it ! Finally, in addition to our final report, I have to write the final article of my project. Today my tutor said me than I could be the first author of this paper and it's incredible for me to publish my first article now. Like me you could write an article or just your report and I have an amazing software that I want share with you : EndNote. What is EndNote ? [1] EndNot it's a software to manage your bibliography when you write an article (or a report). With these you can create a data base with all the article you need by using other data base on the net ( Pubmed, Library of Congress, Ovid, OCLC, SilverPlatter). Use with Word, the software organize your references and formats your bibligraphy. So for our report for exemple we have to put our references with a specific form : “The reference should contain in the same order: Names of the authors (year of publication). Title of the article. Name of the journal (no abbreviations), volume(issue): pages.”, EndNote do that for you ! Moreover when you want add a reference in the middle of your report for example, the software change the order of your references automatically. I think there are many other options but for the moment I didn't have the time to look everything. Unfortunately, the software is note free. I bought it because in Thailand it's not really expensive but I don't know for other country or if you can find it free. I hope this post is useful for you, and if you have some question about the software or anything else, I will be to discuss with you ! See you ! Adèle References : [1] http://www.ritme.com/fr/product/endnote/description
First, we want to know the impact of biting-flies on the cattle productivity. To do that, we work on growing cattle, we call them “feeder cattle” (in our case, young males between 5-12 months of age) we control the quantity of food taken by each group of cattle and we record the weigh of each animal once per week. At the end we want to compare de total gain of weight for each group in function of the quantity of food they took, to know if the biting flies have an effect on the total amount of food ingested and /or on the efficiency to assimilate the food, and on the weight gain (a loss of weight gain is expected due to defense movements/energy loss).
Secondly, we know we have a link between the tail movement of the calves and the density of flies (Hugues Louis Raymond 1987). As H. L. Raymond I do visual counting of tail movement. For each animal I count the tail movement during 3 minutes 6 times along the day. But, this method has some limitation because it takes a long time, requires to observe permanently all animals and thus brings only punctual information so we cannot know the density of fly anywhere and around any herd. To make link between the tail movement and the flies density we cut Wednesday (it is the day when we set up the 3 traps to get an idea of the fly-dentsity) into 6 periods of 2 hours ( between 6am and 6pm ). During each period I count the tail movements and I I collect the cage from the traps, for identification and counting of the biting insects. Thus we will evaluate the link between fly density and tail mouvements. The final idea would be to estimate the lfly density by counting tail mouvements only (we wouls no more use traps in such cases) In the future, we will try to find a way to automate the tail movement counting to get data all along the day and estimate quickly the density of flies. I hope my tasks are more clear now because for me, they are. The most difficult for now is the statistical analyse with Excel and R studio. We didn't do real Bio-statistique during the 2 previous years and I don't have a lot of time to understand everything and it's too bad. If you have the same problem with different thing like T-test, Anova, Ancova , p-values and many other thing or if you have solution I am open to discuss ! See you ! Hi everyone, Remind you, I am in Thailand since one month now and I work on the biting flies impact on the cattle behaviour, especially on the gain of weight of the cattle. This last week I observe something little annoying for the project : insects disappear ! And without insect I cannot observe the defensive tail movement of the cattle. The animal are no more stressed by the biting flies and we have not a significant difference between the gain of weight of our two groups (inside and outside the mosquito net). I tried to understand why my insect disappear, first by discussing with entomology students and researchers, then by analysing my data and finally with bibliography. In the rest of this post I'll speak about the temperature and humidity impact on insect distribution along a day and along a year. What kind of insect I study ? Maybe some of you think I study mosquito but It's not the case. Indeed, my targets during this study are Stomoxys and Tabanidae. Both of them are hematophage insect (only female for Tabanidae) and are harmful for cattle and human too. In addition to the blood spoliation, the insect provoke stress, loss of appetite and energy. They are also a vector for viruses (equine infectious anemia, ovine catarrhal fever), bacteria (Q fever,anthrax) and parasites (Besnoitia, Trypanosoma), with dramatic medical and economic consequences. [1] What is the insect distribution along a day ? Each Wednesday, I put two Vavoua trap and one NZI trap in a field next to the farm. I remove the trap each two hours between 6am and 6pm (6 period for each day) to see the insect distribution along the day and in the same time I take the experimental condition ( temperature and humidity). I have only 5 repetition for the moment but the link between the insect distribution and temperature is really clear. I made the average of the biting insect, of the hematophage insect, of the total of insect and of the temperature for each period. So, when the temperature increase we can see the decrease of the insect density. We can note above 35°C the density of insect is really low. With my 2 hours period I can not see exactly for what temperature insects don't come any more.
For Stomoxys, many studies have been done in several place around the world ( Reunion, Gabon, Thailand and so one). The researcher showed that the optiml temperature for the flies are between 30°C and 32°C. Stomoxys density decrease seriously above 34°C and is almost zero below 14°C. Temperature is the first explication of the density variation but there is some other factor like humidity and rain quantity. This factor explain also the insect distribution along a year.[2][3] What about insect season ? A Thai study showed that 80% of flies were captured in rainy season and 20% during the dry season. So the most important part of insects density is between May and October. Using the data obtained from Kamphaengsean Meteorological Station, they compared this observation with the temperature, the humidity and the rainfall. During this period, the temperature is between 28 and 30°C, humidity around 76% and rainfull around 70mm per month whereas in dry season temperature is above 30°C but humidity it's lower ( around 70%) and there is no rain. [4] Between September and October we can observe a decreasing of the insect density corresponding of sunshine radiation and the increasing of rainfall (200mm) and humidity. According to other studies, this paper show that insect need humidity for the reproduction but high maximal relative humidity have a negative influence on flies. [5] So I hope the disappearance of the insect is because of the daily big rain ( yes, it's the rainy season !) and not the end of the insect season. If it's the end of the insect season, we have to stop the projcet and restart it on May ( of course it's not possible because they have only 2 years to do the other step of the project). I am really surprised about the environmental constraint ! My job here it's really different than our FDV little project. Indeed work on mammal need a really long time scale. For example, here I want to see the growth of the cattle in function of the insect, but we need several months to see something relevant. So restart the experiment for the beginning it's really long and not really possible ( so not in our option ) whereas in microbiology it's more easy because of the fast cellular division, so we can observe something in one day ( now I understand why E.coli is amazing ). So everyday we pray for the end of intensive rain and the comeback of the insects, but we hope also that the cattle will are not sick or something else which could just wreck the last 2 month of our work. Research could be frustrating, just a little References [1] Conseil scientifique Causses et Cévenne http://wikis.cdrflorac.fr/wikis/CsEICC/wakka.php?wiki=FlyScreen [2] Dynamique des populations de Stomoxys calcitrans dans un site urbain, l’Ecole Nationale Vétérinaire de Toulouse, ROUET Diane [3]On the feeding habits of Stomoxys calcitrans L. and sitens Rond., with special reference to their biting cycle in nature. Hafez M., Gamal-Eddin F. M. (1959) Bulletin de la Socièté d'Entomologie d'Egypte. [4]Temperature effects on development and survival of two stable flies, Stomoxys calcitrans and Stomoxys niger (Diptera: Muscidae), Gilles J., David J-F., Duvallet G. (2005) in La Réunion Island. Journal of Medical Entomology 42 (3) [5] Frist survey of seasonal abundance and daily activity of Stomoxys Spp ( Diptera : Muscidae) in Kamphaengsaen Campus, Nakorn Pathom Province, Thailand. MASMEATATHIP R.*, GILLES J.**, KETAVAN C.* & DUVALLET G.*** ( 2006) Hi Everyone, Currently I am in Kampheang Sean Campus in Thailand to work on the FlyScreen project which is coordinated by CIRAD in partnership with Kasetsart University and other institutions around the world. The FlyScreen project consist on the development of colour baited toxic screen for the control of hematophagous flies.[1] Before explain the aims of screen , let me introduce some essentials backgrounds to understand the importance of this project. Facing increasing population, one of the most important question today is : how can continue to product enough food to feed all the humans ? This is not just a question about the quantity of the production. Today we need to improve the production with good quality, safety and keeping safe environment. In different type cattle, we can observe an economic impact of biting flies on the production. [2] ( I will speak about this in an other blogpost). Indeed, biting insect have direct and indirect effect on the cattle health. In the first time they provoke some stress,pain, and blood loss. They can also give some allergic shock and cutaneous infection. In an other hand, biting insects are vector for the blood pathogens, so they can transmit some viruses, bacteria or parasites which can have dramatic impact on the production. [1] So far, for combating biting insects we use huge quantity of insecticide but this method have many issues : residues in meat, milk and environment and now an insecticide resistance for several species of flies. Moreover, this technique is really expensive so the most of the farmer don't use any thing to control the density of biting flies.
With the FlyScreen project, the researcher want to develop trap in optimized the efficiency, low cost and if it possible low polluting. To do that, they imagine some specific blue screen presenting reflectance between 450 and 460 nm. In fact, this colour attract haematophagous insects which are the target but should not attract insect pollinators [3]. Then, they want developing some toxic substances to include in the screen. The goal it's to found substances not toxic for the environment, so growth hormones or insecticides incorporation into polymers with attractant. Finally, they need to evaluate these screen in real condition (in field maybe) to measure the efficiency and the environmental safety. [4] Ok, but now, what is my job during the 3 next months ? Currently it's the beginning of the project. My work in Kampheang Sean Campus is to study the impact of the biting flies on the cattle behaviour. One of my goal is to show if the biting flies have an impact on the gain of weight of the cattle. To do that, I have two groups of 6 beef : one is under mosquito net and the other not. The groups live in the same life condition ( temperature, humidity and quantity of food). Then I observe the cattle behaviour against the insects by counting the tails movement of the animals in function of the insect density ( we can evaluate insect density putting trap next to the farm and identify what kind of insect there are in the environment). Finally we make and analyse blood sample to see if the animals are infected by viruses, bacteria or parasites. So we would like make link between the quantity of food than the cattle eat, their gain of weight and the insect density. If we can show the negative impact of the insect on the cattle with strong data, we warrant the flyscreen project. References : [1]FlyScreen : Development of toxic targets for the control of haematophagous biting flies , GREASE, Dr Marc Desquesnes [2]Economic Impact of Stable Flies (Diptera:Muscidae) on Dairy and Beef Cattle Production, David B. Taylor, Roger D. Moon and Darrell R. Mark. 2012 [3] Evaluation of Different Insecticides and Fabric Types for Development of Treated Targets for Stable Fly (Diptera: Muscidae) Control, JEROME A. HOGSETTE, ALYCE NALLI, AND LANE D. FOIL [4]Development of color baited toxic screens for the control of hematophagous flies http://wikis.cdrflorac.fr/wikis/CsEICC/wakka.php?wiki=FlyScreen/edit |