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PubMed1993

Rapid miniprep isolation of mitochondrial DNA from metacestodes, and free-living and parasitic nematodes.

A method, based on one to isolate supercoiled plasmid DNA from bacterial cells, has been developed to purify mitochondrial DNA (mtDNA) from cestode and nematode tissue easily and efficiently. Starting with as little as 100 mg of helminth tissue, sufficient mtDNA for electrophoretic analysis was extracted. This DNA was essentially free of nuclear DNA and readily digested by restriction endonucleases. Approximately 20% of the mtDNA in helminth tissue was recovered, which is a significant improvement over previously available techniques.

Animals↗
PubMed1996

Strelkovimermis acuticauda n. sp. and Strelkovimermis buccalis n. sp. (Nematoda:Mermithidae) from adult chironomids (Diptera:Chironomidae) from Lake Itasca, Minnesota.

Specimens of 2 mermithid species were obtained from adults of undetermined species of chironomids emerging from Lake Itasca (Clearwater County), Minnesota. Both species have the characteristics of species in the genus Strelkovimermis. The new species are distinguishable from one another and from the 8 currently accepted species in the genus by their small size, shape of the posterior end, length of the buccal funnel, length of the cephalic papillae, location of the mouth, and morphology of the spicule region and vagina. Strelkovimrmis acuticauda n. sp. is unique in possessing an acute posterior end, an auxiliary protractor muscle, and a relatively long vagina, whereas Strelkovimermis buccalis n. sp. is distinguishable from other Strelkovimermis species by its thick cuticle and exceptionally long buccal funnel. The significance of the tail muscles is emphasized as a taxonomic feature to be used in describing future species of Strelkovimermis. A key to the 10 species of Strelkovimermis is provided.

Animals↗
PubMed1996

Egg production by Strelkovimermis spiculatus (Nematoda:Mermithidae).

Egg production by the mermithid nematode Strelkovimermis spiculatus, a parasite of mosquitoes, was examined over a period of 34 days. Oviposition did not occur in the absence of males. Egg production was best when males were continuously present (6.4 x 10(3) +/- 0.9 x 10(3) eggs/female). Fewer eggs were produced when males were removed after 7 days (2.8 x 10(3) +/- 0.2 x 10(3) eggs/female) and oviposition partially recovered after males were returned 11 days later (4.4 x 10(3) +/- 0.5 x 10(3) eggs/female). The nematodes deposited substantially more eggs in sand (6.4 x 10(3) +/- 0.9 x 10(3)/female) than in water (1.9 x 10(3) +/- 0.3 x 10(3)/(female).

Animals↗
PubMed1996

Field trials of combined use of two species of mermithid nematodes to control Anopheles and Culex breeding in China.

The field tests of combined use of Romanomermis yunanensis 2000-3000 larvae per sq m and Romanomermis sp 1000-2000 larvae per sq m in rice fields. Ponds and streams in four cities of China, resulted in 60.8-95.5% parasitism in Culex tritaeniorhynchus, Cx. quinquefasciatus, Anopheles sinensis and An. anthropophagus. This successful use of two species of Romanomermis together not only curb mosquito nuisance it also controls the major vectors of malaria, filariasis and encephalitis B in China.

Animals↗
PubMed1996

[Effects of temperature on the viability and infectivity of preparasitic larvae of Romanomermis yuanenesis].

Romanomermis yuanenesis (Mermithidae: Nematoda) was found in Henan, China (Song and Peng, 1987), which has a broad host range in Culicinae mosquito and has been used successfully in field test for control of culex tritaeniorhynchus, culex fatigans and Aedes albopictus in Sichuan, Yunnan, Guangxi and Henan Provinces. This study was attempted to determine the viability and infectivity of preparasitic larvae in various temperatures. The cultures containing R. yuanenesis eggs were flooded 2h with distilled water, filtered and blocked with 1% agarose. Put the filter paper into water, then the motile preparasites separated from the unhatched eggs and got through the agarose membrane into water. About 200ml water containing preparasites free from eggs were held at 26 degrees C-28 degrees C, 16 degrees C-18 degrees C and -2 degrees C to 2 degrees C for test. The motility or lack of motility was used as the criterion to distinguish the living and dead nematodes. The rate of infection of mosquitoes and the rate of parasitism of nematodes were used to show the infectivity of the preserved preparasites. The results showed that at -2 degrees C to 2 degrees C, more than 90% of preparasitic larvae of R. yuanenesis survived for 8 days and the rate of mosquito infection was 87.5% to 100%, but at 26 degrees C-28 degrees C and 16 degrees C-18 degrees C the survival times of 90% preparasites were only 24 hours and 48 hours respectively. It indicates the low temperature preservation may prolong the survival time and keep the infectivity of these preparasitic larvae.

Animals↗
PubMed1997

Experimental host range studies with Heleidomermis magnapapula (Mermithidae), a parasite of Culicoides variipennis (Ceratopogonidae).

Infectivity of the mermithid nematode Heleidomermis magnapapula, a parasite of Culicoides variipennis variipennis and C. v. sonorensis in dairy wastewater pond habitats, was tested against larvae of aquatic Diptera in the laboratory. Observations were made on preparasite penetration. If the host species could be reared after parasitization, further observations determined nematode development and emergence. Genera in the families Syrphidae (Eristalis), Psychodidae (Psychoda), and Chironomidae (Tanypus), common in wastewater pond habitats, were not attacked. Larvae of Bezzia and Dasyhelea (Ceratopogonidae) also were not attacked. Larvae of Chironomus (Chironomidae) were penetrated, but rapidly encapsulated the nematodes. All Culicoides spp. exposed were readily penetrated by H. magnapapula preparasites. The nematodes successfully emerged from C. v. occidentalis. Some nematode maturation was seen in C. lahontan, and limited adult nematode emergence was seen in C. boydi and C. cacticola. No nematode development was observed in 5 other Culicoides spp. penetrated.

Animals↗
PubMed1998

Experimental transmission of the nematode Echinomermella matsi to the sea urchin Strongylocentrotus droebachiensis in the laboratory.

Three experiments were conducted to investigate the possibility of maintaining the Echinomermella matsi-Strongylocentrotus droebachiensis system in the laboratory. The experiments were performed by injecting E. matsi larvae taken directly from gravid female nematodes into the mouths of sea urchins. In all experiments, this treatment resulted in a higher infection in treated animals than in unmanipulated controls. The successful establishment of larvae indicates that E. matsi has a monoxenous life cycle. The growth of larvae in experimentally infected hosts was slow, indicating that the generation time of the parasite is of the same magnitude as the life expectancy of the host, 1-2 yr. This slow growth rate suggests that considerable resources will be needed to maintain the system in the laboratory.

Animals↗
PubMed1992

[Infective capacity of the parasitic nematoda Romanomermis iyengari (Welch, 1964) (Nematoda: Mermithidae) in mosquito larvae in natural conditions].

The effectiveness of the parasitic nematoda Romanomermis ivengari (Welch, 1964) was proved in 3 breeding sites of Anopheles albimanus (Wiedman, 1821) and Culex Nigripalpus (Theobald, 1901) and 2 spillways for 2 oxidation ponds with Culex quinquefasciatus (Say, 1823) larvae, in the Isle of Youth. The results of the experiments showed the infesting capacity of this nematoda species with 80-100% parasitism in A. albimanus and C. nigripalpus larvae, and 75-80% mortality for C. quinquefasciatus. Besides, the recycling capacity of R. invengari, after its introduction, was proved, confirming its possible use in the control of mosquito larvae of medical-epidemiological importance in the Cuban tropical conditions.

Animals↗
PubMed1994

[Application of a mermithid nematode for the control of mosquito larvae in natural conditions].

Field tests were carried out with the Romanomermis culicivorax nematode (Ross and Smith, 1976) for the control of 3 mosquito species--Anopheles albimanus (Wiedeman, 1821): Culex nigripalpus (Theobald, 1901); and Uranotaenia saphirina (Oster-Sacken, 1868)--in 10 natural reservoirs. The infective nematodes were disseminated in doses of 1 x 10(3) preparasites/m2 of surface area. Increased infestation indices were observed with values ranging from 1.2 to 3.4; mortality percentages fluctuated between 70 and 97% depending on the mosquito species found in the reservoirs. In those reservoirs containing specimens of the 3 species, anophelines showed more susceptibility to parasite infection; culicines showed a lower susceptibility in general. Mosquito larva populations were significantly reduced in the treated reservoirs.

Animals↗
PubMed1994

[Fecundity and embryonal development of Romanomermis culicivorax].

Romanomermis culicivorax (Ross and Smith, 1976) eggs completed the late preparasite curling phase of their embryo development in an average time of 11 days and at a temperature of 25 +/- 2 degrees C. It was also observed that female R culicivorax specimens laid 312 eggs in 13 days, when male and female specimens were placed in a substrate of distilled water with a pH = 4.5.

Animals↗
PubMed1996

[Mass breeding of Romanomermis culicivorax (Nematoda: Mermithidae) in the tropical conditions of Cuba].

To develop the process of mass production on a large scale of the parasite nematode Romanomermis culicivorax Ross and Smith, 1976, under the control tropical conditions of Cuba, it was taken into consideration the standardization of a certain number of variables, such as: utilization of eggs in the process of infectation, dosage, types of water, types of substrate, temperature, culture methods, and storage methods of culture batches. High performances in nematoda and approximately the same amount of females and males were obtained when mosquito larvae of the species Culex quinquefasciatus Say, 1823, were exposed to parasite's infective larvae.

Animals↗
PubMed1995

[An oviposition study of the nematode parasitic on Culicidae Romanomermis iyengari in the laboratory].

Laboratory studies allowed determine that female Romanomermis iyengari Welch, 1964, had a reproductive potential of 1975, 29 eggs in an average time of 21,76 days in distilled water with pH of 4.5 and a temperature of 25 +/- 2 degrees C. It was found that females of this nematode began oviposition in an average time of 14.65 days from the moment of emersion of postparasites of the host larvae. In studying the embryonic development, it was observed that the time elapsed from oviposition to egg hatching and the emersion of preparasites was 290,74 hours. It was determined that the optimum time to begin the exploitation of cultures and obtain a greater yield of preparasites under laboratory conditions is the sixth week of storage.

Analysis of Variance↗
PubMed1998

[Pathogenic effect of the nematode parasite Romanomermis iyengari(Nematoda: Mermithidae) in Aedes aegypti mosquito larvae (Diptera: Culicidae) under laboratory conditions in the state of Oaxaca, Mexico].

Laboratory tests with waters from Aedes aegypti Linneaus (1762) breeding places were made to determine the pathogenic effect of the mermithid nematode Romanomermis iyengari Welch 1964 in mosquito larvae of this species. According to the results obtained, the administration of a dosage of 10:1 (10 preparasitics per mosquito larvae) showed levels of parasitism of 90, 93, 91, and 85% in mosquito larvae in the I, II, III, and IV stage, respectively. With the highest dosage of 20:1 (20 preparasitics per mosquito larvae) there were obtained levels of parasitism with values of 98, 97, 93 and 89% among larvae in the I, II, III, and IV stage, respectively. Generally, the values of the physical and chemical parameters such as pH, conductivity, oxygen, and chlorides calculated in these waters did not affect apparently the infective capacity of the preparasitics of R. iyengari.

Aedes↗