Webmedcentral - Parasitology ArticlesThe Parasitology articles published by Webmedcentral
http://www.webmedcentral.com
2024-03-29T14:14:26+01:00webmedcentral logo
http://www.webmedcentral.com/
http://www.webmedcentral.com/images/Header_Logo.giftext/html2010-09-21T16:39:49+01:00http://www.webmedcentral.com/Mr. Sudhansu MishraFish Disease Management in Integrated Farming System
http://www.webmedcentral.com/article_view/663
Integrated Fish Farming (IFF) is a sustainable-agriculture technology practiced widely in Asia and other regions of the world. This is very popular, advanced and widely practised in China. Hence most culture methods have either been derived from Chinese methods or modified suitably as per the regional requirements. This integrated technology can offer farmers economic improvements while lessening the adverse environmental impacts of fertilizer based-farming. IFF systems typically involve a combination of fish polyculture, integration of agricultural production (livestock and/or crops) with aquaculture, and on-farm waste and wastewater recycling. Evolved on the principles of productive recycling of farm wastes, fish- livestock farming systems are recognized as highly assured technologies for fish cultivation. Actually in India, the concept of composite fish culture was developed and popularised by ICAR – Fishery Scientists in late seventies under a coordinated composite fish culture project. This comprises the culture of 3 indigenous species of fish viz. rohu, catla and mrigal and 3 exotic fish i.e silver carp, grass carp and common carp, keeping in view their different food habit and habitat. The system provides meal, milk, eggs, fruits, vegetables, mushroom, fodder & grains in addition to fish. It utilizes the pond dykes which otherwise remain unutilized for the production of additional food and income to the farmer. The possible integrated farming systems as commonly practised are : a) Fish cum Agriculture System : i) Fish cum Paddy culture, ii) Fish cum papaya, iii) Fish cum Mulberry and iv) Fish cum Mushroom b) Fish cum Animal husbandry System: i) Fish cum Dairy, ii) Fish cum piggery, iii) Fish cum Rabbit farming, iv) Fish cum poultry and v) Fish cum DuckeryConcept of Fish Health management in integrated farming:Occurrence of disease in a fish population depends on interactions of variables defined for the host, the pathogen and the environment. Absence of pathogens would reduce the potential for adverse environment to influence disease outbreak. The dose or the number of pathogens, their route of entry to host and the duration of the exposure directly influence the severity of subsequent infection.A.The environmentPoor water quality has been recognized as one of the main factors responsible for occurrence of disease problems in aquatic animals. Incidence and severity of infectious diseases are very often dependant on the quality of the environment in which the animal lives. In other wards the quality of environment can indicate the health status of animals. Thus, the first and foremost important step in controlling infectious diseases is by maintaining the best quality environment possible in the culture unit.a) Removal of unwanted aquatic weeds : Unwanted aquatic weeds are needed to be removed from fish pond as it reduces the pond productivity. These unwanted aquatic weeds could be removed manually, mechanically, chemically and biologically. Manual removal method is better. Grass carp, java puthi, tilapia, etc. are good biological agent in removing aquatic weed from fish pond. Chemicals used in the removal of aquatic weeds from fish pond are: i) 1.2-4 D or 2-4 D Ester at the rate of 5-6 kg/Ha ii) Simazine at the rate of 0.5 tp1.0 mg/lit water for floating weeds like Eichornia, duck weed and Algae type, iii) Super phosdphate at 500mg/lit pond water for submerged weed like hydrilla, valisnaria etc. Some time a thick layer of algal bloom of brown or green colour is seen over the water surface of pond. This can be removed from fish pond by using a piece of split bamboo followed by liming based on water pH. Chemicals like copper sulphate @0.1- 0.5 mg/lit. of water also helps in controlling this bloom. Noxious gases and the effect of other substances of pond bottom mud can be reduced by repeated netting or by moving a rope through the pond bottom mud.b) Liming : Liming helps in maintaining the pHof fish pond water. This helps in increasing the natural productivity of the pond. Liming also helps in maintaining the cultured fish stock disease free. It is done based on the soil and water pH.c) Fertilization: Fertilization increases the natural food availability in the pond. It is believed that manuring alone can increase the production of the pond by 75%. Organic manure like cow dung, poultry dropping, etc are used commonly in fish pond. Since animal excreta is rich in nitrogen and phosphorous,, there is no need of using extra fertilizer as mentioned above in this type of integrated farming.d) Water quality management : The success of fish culture largely depends upon the water quality of the stocking pond. Water quality is defined as suitability of water for the survival and optimum growth of cultured fish. The higher the intensity of culture the will be the water quality problem. In water quality management we regulate the environmental conditions so that are within the optimum range for the cultured stock.B. The Fish :Selection of suitable fish species for culture is very important aspect for integrated fish farming. Numbers of fish species are available for composite fish culture. But a species selected for culture should have the following characters- i) Fast growth rate ii) Ability to withstand changing physico-chemical and biological conditions of the pond water iii) Adaptability to crowded conditions and resistance to diseases iv) Good food conversion efficiency v) Acceptability of supplementary and natural food and vi) Good market value. Normally Rohu (Labeo rohita), Catla (Catla catla), Mrigal (Cirrhinus mrigala), Silver carp (Hypophthalmichthys molitrix), Common carp (Cyprinus carpio), Grass carp (Ctenopharyngodon idella), Tilapia (Oreochromis mossambicus), Magur (Clarias batrachus),Java puthi (Puntius javanicus), Freshwater prawn (Macrobrachium rosenbergii), and in some cases Penaeus monodon etc. are cultured. The stocking density depends on the species, culture period, desired individual size and intensity of management. In composite fish culture in stocking pond fish seed of 10- 15 cm length (fingerling) is stocked at the rate of 7000- 8000 nos. / ha. (900- 1000 nos. / bigha). Normally followed 6 species combination are i) Catla (30%), Rohu (20%), Mrigal (10%), Common carp (5%), Silver carp (20%) and Grass carp (15%). In some cases Tilapia species are included by balancing Silver carp and Grass carp combination.text/html2010-09-27T07:17:49+01:00http://www.webmedcentral.com/Dr. Philip B McKennaAn updated checklist of helminth and protozoan parasites of birds in New Zealand
http://www.webmedcentral.com/article_view/705
A combined and updated checklist of helminth and protozoan parasites of birds in New Zealand is provided. This checklist, which is divided into two parts, includes a total of 203 parasites (68 nematodes, 40 cestodes, 44 trematodes, 11 acanthocephalans and 40 protozoans) from 116 hosts.text/html2010-09-28T19:09:03+01:00http://www.webmedcentral.com/Dr. Subhasish BandyopadhyayPrevalence of Gastrointestinal Parasite in Goats in Shillong, Meghalaya, India
http://www.webmedcentral.com/article_view/777
A study was conducted regarding the level of burden of gastrointestinal Parasites in goat slaughtered for human consumption in Shillong, Meghalaya during June,2001 to June,2006. A total of 250 gastrointestinal tract were examined for adult parasites. The intensity of parasitic infection was recorded maximum in rainy season and least during winter. The parasite recorded was O. venulosum, O. columbianum, Haemonchus contortus, Bunostomum trigonocephalu, Trichuris species, Trichostrongylus colubriformis, Moniezia expansa, Moniezia benedeni, Gaigeria pachysalis, Amphistom species. One of the interesting finding was the prevalence of Haemonchus contortus in reticulum in 76.8% cases.text/html2011-03-02T19:00:06+01:00http://www.webmedcentral.com/Mr. Laban N IreriLaboratory Evaluation of Selected Medicinal Plant Extracts in Sugar Baits and Larval Food Against Phlebotomus Duboscqi Neveu Lemaire (diptera: Psychodidae), A Vector for Cutaneous Leishmaniasis in Kenya
http://www.webmedcentral.com/article_view/1651
Introduction; The efficacy of Tagetes minuta (Asteraceae), Acalypha fruticosa (Euphorbiaciae) and Tarchonanthus camphoratus (Compositae) extracts were evaluated for the control of Phlebotomus duboscqi while incorporated in sucrose. This is the first time plant extracts have been used in sucrose baits against sand flies as opposed to environmentally unfriendly synthetic insecticides.Materials and methods; The plants were collected from Marigat area, Baringo district in the Rift Valley Province of Kenya, an endemic area for leishmaniases. Extraction was done using N-hexane, dichloromethane, ethyl acetate and methanol.Results; The extracts showed significant mortality (P< 0.05) to both males and females and had comparable LD50 values in Tagetes minuta and Acalypha fruticosa extracts bioassays. The lowest LD50 value for females was 10.6mg/ml in ethyl acetate bioassays in Tagetes minuta and Acalypha fruticosa extracts, while the highest was 12.0 mg/ml in Tagetes minuta methanol extract. Males had the lowest value of 9.9mg/ml in Tagetes minuta methanol extract, while the highest was in Acalypha fruticosa methanol extract with a value of 15.5mg/ml. Results however showed that there was no significant mortality (P> 0.05) difference between males and females but mortality significantly differed (P<0.05) at various concentrations. Tarchonanthus camphoratus and combined extracts however showed weaker insecticidal properties than from separate extracts. Feeding the larvae using extracts in larval food and plain powders nonetheless revealed no larvicidal properties in the plant samples.Conclusion; The results showed potent properties and may guide future research initiatives aimed at controlling sand flies using sugar baits as alternative approaches to conventional methods.
text/html2011-04-26T19:35:05+01:00http://www.webmedcentral.com/Dr. Ulku Karaman An Infection Case of Cyclospora Cayetanensis in a Patient with Chronic Thyroiditis
http://www.webmedcentral.com/article_view/1899
Cyclospora cayetanensis, which is a protozoon, falls into the coccidia subclass of Apicomplexa branch. It has been reported that this parasite can infect all age groups and cause diarrhea among patients with non-immune deficiency and immune deficiency. Moreover, it is known that the prevalence of C. cayetanensis increased in tropical and subtropical regions. In the present case, a 45 year-old female patient having L-tyrosine treatment for chronic thyroiditis and traced as eutiroid visits the interior disease polyclinic with complaint about severe diarrhea for one week. Following examination for parasite using Kinyoun's acid-fast staining method revealed C. cayetanensis oocysts. The parasite in the present case can be an agent of persistent diarrhea especially among patients with suppressed immune system. Moreover, this case is also presented to note that it can be a cause of diarrhea among non-immune deficiency patients based on the case stories reported.text/html2011-10-25T12:44:37+01:00http://www.webmedcentral.com/Dr. Fatik B MandalDoes Virulence Offer Benefit to the Parasite?
http://www.webmedcentral.com/article_view/2363
Parasites and hosts remain locked in a continuous struggle for survival. The co-evolutionary interactions between the hosts and parasites influence both the host and parasite. Parasite pathogenesis and host defense act in a concert to shape the evolution of virulence. There are various theories on the evolution of virulence in parasite. Host mortality, host resistance, host recovery, mutation, co infection, super infection, host heterogeneity, and mode of transmission have been described for explaining the virulence in parasite. The evolution of parasite virulence focuses on the tradeoff between costs and benefits of the parasite from the host exploitation and appears to be satisfactory. The interaction between the hosts and parasites is multidimensional, dynamic and exceedingly complex. A number of factors perhaps act to shape the level of parasite virulence. Generally, virulence is not beneficial to most of the parasites. Virulence attains a maximum level due to the mutation which is induced by the changing environment. A thorough understanding of pathogenesis including a complete inventory of spatial and temporal expression of genes by both hosts and parasites, from the time of exposure to the final resolution of infection, would contribute a lot in our understanding of evolution of parasite’s virulence.text/html2011-11-18T16:52:44+01:00http://www.webmedcentral.com/Mr. Laban N IreriPotential Effects Of Pyrethrin Incorporated In Sucrose Baits Against Phlebotomus duboscqi Neveu Lemaire (Diptera: Psychodidae) In Leishmaniasis Control Strategies.
http://www.webmedcentral.com/article_view/2129
Background: Due to challenges of controlling leishmaniasis in Kenya through the vector, the efficacy of pyrethrin EC (Pymos™ 0.6% W/V) a mosquito adulticide was evaluated against Phlebotomus duboscqi while incorporated in sucrose as a possible complementary method.Methods: Pyrethrin was prepared into concentrations of 0.08, 0.25 and 0.5 mg/ml using 10% sucrose. Ten male and female sand flies were each aspirated into jars and fed separately with the prepared solutions using cotton wool pads placed atop experimental jars and mortality monitored each day. The experiments were replicated three times.Results: Significant mortality (P< 0.05) for both sexes was observed. The concentration of 0.08mg/ml gave low adult mortality in 24 hours but amplified with time. In the 0.25 bioassay, mortality of females was 10 (33.3%) and males had 21 (70%) in 24 hours. The LD50 for females and males tied at 0.1 mg/ml in 48 hours of exposure. The concentration of 0.25 mg/ml was ideal at 48 hours of feeding where majority of the sand flies succumbed to the insecticide. There were significant mortality differences (PP>0.05) was observed in male and female mortality at 48 hours of exposure however. Although we cannot rule out sand fly mortality due to contact with the test material, the results of this study however suggest that control strategies using low-dose pyrethrin-sugar combinations as baits may be effective against phlebotomine sand flies and other sugar feeding pests of medical importance.text/html2013-02-25T07:28:39+01:00http://www.webmedcentral.com/Dr. Rimma ZurabianVariability Between Infrapopulations of Infective and Non-Infective Taenia Crassiceps WFU Cysticerci
http://www.webmedcentral.com/article_view/4064
Taenia crassiceps WFU strain metacestodes obtained from continuous mice passages and dog-derived T. crassiceps metacestodes were used to produce infrapopulations. Individual mice were infected with a single intraperitoneal cysticercus and examined 4 months post-infection. Three cloned infrapopulations were obtained from the WFU strain (WS), which had lost the ability to grow into tapeworms in experimental hamsters after being propagated in mice for four years. Twelve cloned isolates were obtained from mouse cysticerci recovered after intraperitoneal inoculation of whole untreated eggs obtained from a dog tapeworm which had been fed WS cysticerci. The metacestodes from the dog-derived T. crassiceps strain (DS) recovered the ability to grow adult tapeworms in experimental hamsters. Analysis of randomly amplified polymorphic DNA (RAPD) from each infrapopulation used to construct a Neighbor-joining tree showed that the WS clones that had been propagated for long periods in mice only were closely related in amplified DNA analysis, while DS clones exhibited differences in DNA fragments between each other and the mouse-propagated WFU strain clones.