In vitro cultivation of Brugia malayi and Brugia pahangi infective larvae to fourth and fifth stage (original) (raw)
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Parasites & Vectors, 2015
Background: Schistosoma haematobium is the most widespread schistosome species in Senegal and occurs in several regions of the country especially in the Sudan-Sahelian zone. The aims of the study were i) to determine the freshwater species ii) to ascertain the role of the identified snail species in the transmission of S. haematobium and iii) to study the impact of drought on the snails. Methods: Snails were sampled each year in 17 sites from July to November-December 2012 and 2013. At each snail survey, snails were grouped by village, counted, identified according to shell morphology and the rates of schistosome cercarial shedding recorded. The shell height of the snails collected in July was measured and classified into four groups according to their size in order to determine those that are open to aestivation. Results: B. senegalensis and B. umbilicatus were the only snails intermediate hosts collected in the Niakhar study area. B. senegalensis is found in all the 17 sampling sites while B. umbilicatus was only found in one site out of the many surveyed. The total number of B. senegalensis collected in 2012 and 2013 was 1032 and 8261 respectively. A total of 901 and 6432 B. senegalensis were tested for Schistosoma spp. infestation in 2012 and 2013 respectively. For B. umbilicatus, 58 snails were collected and tested in 2012. In 2013, 290 were collected and 281 tested. The overall rates of schistosome cercarial shedding were 0 % in 2012 and 0.12 % in 2013 for B. senegalensis and 13.79 and 4.98 % in 2012 and 2013 respectively for B. umbilicatus.
New challenges in schistosomiasis control in Morocco
Acta Tropica, 2000
Cases of schistosomiasis were first detected in 1914. However, there is strong evidence that it was prevailing in the southern part of Morocco long before then. As reported from different African countries, over the last three decades, the development of irrigation has led to the spread of the disease to the north and centre of the country. Thereafter, a national programme of schistosomiasis control was launched by the Ministry of Health in 1983. The programme was based on case detection and treatment, snail control using chemicals, and health education. It has succeeded in reducing the prevalence and intensity of infection to a level low enough to allow an elimination programme to be launched in 1994. The aim is to reach a complete elimination of the disease by the year 2004 in all provinces affected. Though substantial progress was made since the programme started, there is a potential risk of outbreaks in many affected provinces. Therefore, an integrated approach including measures against the intermediate host is needed to reach the goal of elimination. The present paper sheds some light on the features of schistosomiasis in Morocco and presents an evaluation of environmental methods of control of Bulinus truncatus in Tessaout Amont and Akka oasis irrigation schemes. The role of community involvement in planning and implementing environmental measures against the snail intermediate host in modern and traditional irrigation schemes is also discussed.
648 snails comprising 392 (60.5%) Bulinus globosus (Morelet, 1866) and 256 (39.5%) Biomphalaria pfeifferi (Krauss, 1848) obtained from Samaru stream and ABU dam between April and September 2007 were examined for cercariae. Of this total, 355 snails were obtained from Samaru stream while 293 snails were obtained from A.B.U dam. 247 (69.58%) of the snails from Samaru stream were B. globosus and 108 (30.42%), B. pfeifferi. Similarly, 145 (49.49%) B. globosus and 148 (50.51%) were gotten from A.B.U dam. Two schistosomes were observed during the study; Schistosoma mansoni and Schistosoma haematobium with the former being more prevalent (20.31%) than the latter (18.37%).
Journal of Parasitology
In Kenya, schistosomes infect an estimated 6 million people with .30 million people at risk of infection. We compared compatibility with, and ability to support and perpetuate, Schistosoma mansoni of Biomphalaria pfeifferi and Biomphalaria sudanica, 2 prominent freshwater snail species involved in schistosomiasis transmission in Kenya. Field-derived B. pfeifferi (from a stream in Mwea, central Kenya) and B. sudanica (from Nawa, Lake Victoria, in western Kenya) were exposed to S. mansoni miracidia isolated from fecal samples of naturally infected humans from Mwea or Nawa. Juvenile (,6 mm shell diameter), young adult (6-9 mm), and adult snails (.9 mm) were each exposed to a single miracidium. Schistosoma mansoni developed faster and consistently had higher infection rates (39.6-80.7%) in B. pfeifferi than in B. sudanica (2.4-21.5%), regardless of the source of S. mansoni or the size of the snails used. Schistosoma mansoni from Nawa produced higher infection rates in both B. pfeifferi and B. sudanica than did S. mansoni from Mwea. Mean daily cercariae production was greater for B. pfeifferi exposed to sympatric than allopatric S. mansoni (583-1,686 vs. 392-1,232), and mean daily cercariae production among B. sudanica were consistently low (50-590) with no significant differences between sympatric or allopatric combinations. Both non-miracidia-exposed and miracidia-exposed B. pfeifferi had higher mortality rates than for B. sudanica, but mean survival time of shedding snails (9.3-13.7 wk) did not differ significantly between the 2 species. A small proportion (1.5%) of the cercariae shedding B. pfeifferi survived up to 40 wk post-exposure. Biomphalaria pfeifferi was more likely to become infected and to shed more cercariae than B. sudanica, suggesting that the risk per individual snail of perpetuating transmission in Kenyan streams or lacustrine habitats may differ considerably. High infection rates exhibited by the preferential self-fertilizing B. pfeifferi relative to the out-crossing B. sudanica point to the need to investigate further the role of host breeding systems in influencing transmission of schistosomiasis by snail hosts.
Basrah Journal of Veterinary Research, 2016
Samples of the snails were collected from site in Al-Rasheed distract (30 km) southern of Baghdad. Isolation, identification and acclimatization to laboratory circumstances made within the laboratory. Several toxic parameters as NOEL, Threshold, different values of ED and LD were determined in this study. The ED50 of S. officinalis and Copper sulfates to B. truncatus were (8.8 and0.04g/L) respectively. The LD50 of S. officinalis and Copper sulfates to B. truncatus were (20 and 2.2 g/L) respectively.The study showed that the extracts of S. officinalis were less effective than CuSO4. The results improved that the toxicity of extracts was dose and time dependent. The present work concluded to ability to use the target extracts in control of snails the middle host of urinary Schistosomiasis. Schistosomiasis (Bilharziasis) may be a major public pathological state within the world. It affects 240 million people worldwide. Millions of people are suffering from severe morbid because of Schistosomiasis.The type parasitic worm Schistosoma haematobium is the causing of urogenital Schistosomiasis and the types S. guineensis, S. intercalatum, S. mansoni, S. japonicum, and S. mekongi are the causing of intestinal Schistosomiasis. Iraq is a one of countries suffering from urogenital Schistosomiasis. Baladruz is one of endemic distract of Diyala province with Bilharziasis. Al-Bzania River in Baladruz is considers as a foci of disease victor. According to statistics of health associations and many studies in the region, 18% of Baladruz populations affects with Schistosomiasis. Many causes were effected of distribution of Schistosomiasis in the region as authorities' factors like using of river water as a wash place and swim especially with children whereas it specialized to palms irrigation [1-3].The life cycle of the disease is depending on factors such as presenting of Bulinus truncatus snail and contacting with water infested with
2015
Schistosomiasis is a vector-borne disease, caused by parasites of the genus Schistosoma. The disease is endemic in several countries in the world including Nigeria. The parasite that causes schistosomiasis requires the intermediate host (snails), humans, slow flowing or stagnant water to cause infection. The snails that transmit human schistosomiasis are of the genus Bulinus (which causes urinary schistosomiasis and are transmitted by Schistosoma haematobium) and Biomphalaria (which transmit intestinal schistosomiasis and can be transmitted by Schistosoma mansoni). These snails could be controlled by studying their ecology. Elimination of these snails is one suitable approach through which the parasite can be controlled. Besides environmental manipulation and application of synthetic molluscicides, the use of plant based molluscicides can be effective method for the control of the snails. Some plant with base molluscicides includes Azadirachta indica, Jatropha Curcas, Jatropha glauc...
Compatibility of Schistosoma mansoni Cameroon and Biomphalaria pfeifferi Senegal
Parasitology, 2000
The vectorial capacity of Biomphalaria pfeifferi from Ndiangue, Senegal, was investigated with an allopatric isolate of Schistosoma mansoni from Nkolbisson, Cameroon. The snail infection rate after exposure to a single miracidium per snail (MD1) was 56·3%, and 91·6% for snails exposed to 5 miracidia per snail (MD5). The minimum pre-patent period was 21 days. The mean total cercarial production for the MD1 group was 18511 cercariae per snail, and 9757 cercariae for the MD5 group. The maximum production of cercariae for 1 day was 4892 observed in a snail from the MD1 group at day 43 post-infection. The mean longevity of snails was higher in group MD1 (88 days p.i.) than in group MD5 (65 days p.i.). The chronobiological emergence pattern revealed a circadian rhythm with one shedding peak at mid-day. Comparisons are made with the vectorial capacity of the sympatric combination of B. pfeifferi Senegal/S. mansoni Senegal.
2007
Schistosomiasis is an important parasitic disease that infects humans. Among the main species of schistosomes infecting humans is Schistosoma mansoni and S. haematobium. Snails of various genera, such as Biomphalaria alexandrina and Bulinus truncates, act as intermediate hosts and play a major role in the transmission of schistosomes. Transmission from human to snail is under the influence of the ciliated miracidium larvae that hatch from the eggs of the parasite voided in the faeces or urine. After a period of asexual multiplication in the snail, a second aquatic larval stage, the cercaria, emerges and infects human by direct penetration of the skin. The present work was carried out on Biomphalaria alexandrina snails, the intermediate host of Schistosoma mansoni. Snails were collected from various sites in south western Saudi Arabia. Their progeny were reared in the laboratory under standard conditions. Different biological experiments were carried out to determine the susceptibility level in the various populations of snail. The miracidia were obtained by isolating viable ova of the hatching parasite from faeces of infected individuals (human and mice). Different sets of regulated experimental infection of snails with the miracidia of Schistosoma mansoni were preformed. The effect of miracidial density, water temperature, miracidial age, size of snails, as well as light and darkness were investigated. The study revealed that the infection rate increased as the number of miracidia used increased (1, 60%; 2, 60%; 3, 70%; 5, 80%; 15, 90%; and 20, 90%). No significant increase of infection rate was achieved at higher water temperatures (at 15°C: 65% with newly hatched miracidia; 75%, with 15 minutes miracidia; 85% with 30 minutes miracidia; 95% with 45 minutes miracidia and 100% with 60 minutes miracidia. At 20°C: 75% with newly hatched miracidia; 80%, with 15 minutes miracidia; 90%, with 30 minutes miracidia; 95% with 45 minutes miracidia and 100% with 60 minutes miracidia). Similar results were obtained at 25°C and 30°C. However, the infection rate decreased in relation to snail size increase. At snail size 2-4 mm the infection rate was 90%, the rate decreased to 85% at 4-6 mm and 6-8 mm size, while at 8-10 mm size the rate was 80%. At 10-12 mm and 13-15 mm size the rate dropped to 75%. Light and dark conditions had a significant difference on the infection rate (40% in darkness and 90% in light). Laboratory observations also indicated that some of the snails exposed to infection with miracidia of the respective parasite developed infection and produced cercariae, while the rest remained uninfected.