Disease Ecology - Science topic

Depending on the species and their habitat, a co-evolution of the animal and what it eats occurs over generations of time. I would try to figure out what positive or negative feed backs have occurred or are occurring between the animal and what it eats. Especially important would be identifying any positive selections occurring in morphology/physiology.

Dear colleagues

One small note: if humans become infected after ingestion, as some pet animals do, the infective stage should be an L3, because eggs are morulated when shed in faeces and are not infective. These eggs will develop till they have an L1 inside, after some hours in the environment. Then L1 hatch and must go through two molts before reaching the L3 stage, the real infective stage.

These L3 can be easily ingested by children/adults eating raw vegetables in salads, or while doing geophagia, when playing on the ground without washing their hands or while doing gardening without gloves.

There are some eosinophilic enteritis reported in Australia since the 1990s, whose nematodes were collected and identified after colonoscopy, and after this report, parasitologists also began to consider both cutaneous and enteric syndromes caused by this agent in humans.

Best regards

Luís Carvalho

Parasitology and Parasitic Diseases

Faculty of Veterinary Medicine

Lisbon University

Portugal

 thans for all

Hello,

Mostly a parasite, on gaining entry into the body of the host, migrates within the host body in search of a suitable site and finally becomes established in that region of the host body where it lives and reproduces. However, sometimes the parasite happens to reach a place which is not its usual site of localization. Such parasite which fails to reach its normal destination is termed as aberrant.

The parasites are also categorized into two different types on the basis of the number of hosts required for the completion of their life history. The parasites that complete their life cycle in one host only are called as monogenetic. Some parasites display alternation of the host as well as alternation of generation. These parasites which require two different hosts for the completion of their life cycle are called as digenetic. Generally, out of the two hosts one is a vertebrate host which is referred as definitive or final or primary host and the other is invertebrate host, commonly known as secondary or intermediate host.

You mention liver, so if you are referring to histological detection of hypnozoites in primates (rather than to avian haemosporidian infections), the answer is "No". It would be like looking for a needle in a haystack. Hypnozoites are directly sporozoite-derived and relatively few sporozoites are inoculated by mosquitoes. It is difficult enough to find hypnozoites in the liver (a primate liver is large) after injection of massive numbers of sporozoites experimentally. As for avian infections, finding schizonts in whatever tissue(s) histologically would not reveal for certain whether or not an abortive infection is involved (see the original question).

Dear Uma,

If you are interested in spatial processes (cartography, patterns, distributions...) or the interaction of the parasitism process with social or ambiental factors, for example; then may a collaboration between us could be productive.

Yours sincerely,

Daniel.

Dear Paul Chisholm

Usually we Called it age resistance, its not only for transmission by vectors, also affected by interference , signals and pathways, movement protein, plant hormone (http://www.springer.com/us/book/9789401792844)...

Pls. find the attached files

page 287 in: IRRI, 1969 The Virus Diseases of the Rice Plant: Proceedings of a Symposium at the International Rice Research Institute, April, 1967 International Rice Research Institute

Hoping this will be helpful

Regards

Prof. Houda Kawas

I like the old stand by Hymenolepis diminuta in Rattus. Also, easily useable are gregarines in Tenebrio. Scott

We are working almost 10 years with Hellgren's et al. (2004) and Waldenstrom et al. (2004) protocols for screening avian blood samples . We also do a lot of microscopy for comparison of sensitiveness with PCR protocols (Valkiunas et al. 2008, J Parasitology). For detection of haemosporidian parasites with light parasitemia, these nested PCR protocols are very good. The biggest issue is co-infections. As Javier said, if there is co-infection in the sample, it should be seen on electropherogram as double peaks in particular places. However, after comparison with microscopy results we see that its not the case in many samples. We tried different primers and it seems that this selective amplification exist with other primers as well. In most of the studies based on PCR screening the data shows that single infections are predominant and that co-infections exist but are not that prevalent. By microscopy co-infections are detected significantly more often (Valkiunas et al. 2008, J Parasitology). 

We should also remember that PCR's detect DNA of parasite, but does not show if that DNA is from infective stage (gametocyte) or other stage which can be dad end for further development (Valkiunas et al. 2009, J Parasitology, 95). In this case the bird should not be assigned as the host.      

To conclude, at present we have good, sensitive primers (mentioned above) for light infections for parasites of Plasmodium, Haemoproteus and Leucocytozoon, but co-infections (Haemoproteus/Haemoproteus,  Plasmodium/Haemoproteus or Plasmodium/Plasmodium) is still big problem when you do only PCR's. The best is combination of PCR and microscopy so far.

   

Regarding the "evolution of infectious diseases" there are quite numerous papers in the field of palaeoparasitology, but nearly exclusively on material from archaeological and Quaternary contexts. Some recent review papers are:

Araújo, A., Reinhard, K., Leles, D., Sianto, L., Iñiguez, A., Fugassa, M., Arriaza, B., Orellana, N., Ferreira, L.F. 2011. Paleoepidemiology of intestinal parasites and lice in pre-Columbian South America. Chungara, Revista de Antropología Chilena: 43(2): 303-313.

Beltrame, M.O., Souza, M.V., Araújo, A., Sardella, N.H. 2014, in press. Review of the rodent paleoparasitological knowledge from South America. Quaternary International.

Bryant, V.M., Reinhard, K.J. 2012. Coprolites and archaeology: the missing links in understanding human health. New Mexico Museum of Natural History and Science Bulletin 57: 379-387.

Frías, L., Leles, D., Araújo, A. 2013. Studies on protozoa in ancient remains - A Review. Mem Inst Oswaldo Cruz 108(1): 1-12.

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In case you are interested in pre-Quaternary parasites, this is the reference list (not textbook or review-type papers):

da Silva, P.A., Borba, V.H., Dutra, J.M.F., Leles, D., da-Rosa, A.A.S., Ferreira, L.F., Araujo, A. 2014. A new ascarid species in cynodont coprolite dated of 240 million years. Anais da Academia Brasileira de Ciências 86(1): 265–269.

Dentzien-Dias, P.C., Poinar, G.Jr., de Figueiredo, A.E.Q., Pacheco, A.C.L., Horn, B.L.D., Schultz, C.L. 2013. Tapeworm Eggs in a 270 Million-Year-Old Shark Coprolite. PLoS ONE 8(1): e55007. http://dx.doi.org/10.1371/journal.pone.0055007

Hugot, J.P., Gardner, S.L., Borba, V., Araujo, P., Leles, D., Da-Rosa, Á., Dutra, J., Ferreira, L.F., Araújo, A. 2014. Did the dinosaurs have pinworms? Discovery of a 240 million year old nematode parasite egg in a cynodont coprolite sheds light on the early origin of nematode parasites in vertebrates. Parasites & Vectors 11-2014.

Poinar, G., Boucot, A.J. 2006. Evidence of intestinal parasites of dinosaurs. Parasitology. http://dx.doi.org/ 10.1017/S0031182006000138

Tweet, Chin, K., Murphy, N. 2006. Paleobiological implications of diminutive invertebrate burrows within probable gut contents of a hadrosaurid dinosaur from the Upper Cretaceous (Middle Campanian) Judith River Formation of Montana. Geological Society of America, Abstracts with Programs 38(7), p. 476. https://gsa.confex.com/gsa/2006AM/finalprogram/abstract_112739.htm

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Some recent review papers on palaeovirology:

Aswad, A., Katzourakis, A. 2012. Paleovirology and virally derived immunity. Trends in Ecology and Evolution 27(11): 627-636.

Feschotte, C., Gilbert, C. 2012. Endogenous viruses: insights into viral evolution and impact on host biology. Nature Reviews / Genetics 13, April 2012: 283-296.

Katzourakis, A. 2013. Paleovirology: inferring viral evolution from host genome sequence data. Phil Trans R Soc B 368: 20120493. http://dx.doi.org/10.1098/rstb.2012.0493

Don't use the API system-waste of money for Salmonella. The comment from M. Musgrove is by and large accurate, apart from the fact that reptiles are cold-blooded and may carry both serovars of S. enterica and also Salmonella bongori. As such culture is still arguably the better method. Selenite enrichment followed by a selective media- Brilliant Green, XLD, RV or one of the newer commercial agar should work relatively well. If you wish PCR is a reasonable confirmatory test for S. enterica with genes such as invA and the aforementioned hilA found in visually all isolates. If you want to type the isolates then MLST should also tell you the serotype and is cheaper unless you already have the full set of typing sera.

Published online 17 February 2011 | Nature | doi:10.1038/news.2011.102

Wu D, Cai S, Chen M, Ye L, Chen Z, et al. (2013) Tissue Metabolic Responses to Salt Stress in Wild and Cultivated Barley. PLoS ONE 8(1): e55431. doi:10.1371/journal.pone.0055431

Araus, José Luis , Slafer, Gustavo A. , Royo, Conxita and Serret, M. Dolores(2008) 'Breeding for Yield

Potential and Stress Adaptation in Cereals', Critical Reviews in Plant Sciences, 27: 6, 377 — 412

Spiders and mygalomorphs display an important role as predators in many ecosystems. This contributes to the regulatory function of their prey populations which may limit demographic explosions that may include disease vectors, and/or herbivores. In this sense they represent potential allies for disease regulation and plant productivity. On the other hand, and as Dr Mario Ruiz-Gonzalez explained, they present several adaptations to predate at different ecosystem levels (soil surface, subsoil, understory, trees), and on different prey types depending on the species (even if the most of Arachnids are rather generalists within their preying strategy). Each of these strategies and strata can be considered as predation traits. The diversity of traits is a good indicator of a complex trophic web, while the abundance of a given trait is an indicator of abundance of a particular resource (prey type). Therefore even if their diversity and abundance is potentially beneficial, I think they might also constitute indicators of prey abundance.

But as suggested, if the ecosystem features remain constant, varying only an increased abundance and/or diversity of spiders, I think that both disease control and productivity might be enhanced.