Skip to main content

Nature limits filarial transmission


Lymphatic filariasis, caused by Wuchereria bancrofti, Brugia malayi and B. timori is a public health problem of considerable magnitude of the tropics and subtropics. Presently 1.3 billion people are at risk of lymphatic filariasis (LF) infection and about 120 million people are affected in 83 countries. In this context it is worth mentioning that 'nature' itself limits filarial transmission to a great extent in a number of ways such as by reducing vector populations, parasitic load and many other bearings. Possibilities to utilize these bearings of natural control of filariasis should be searched and if manipulations on nature, like indiscriminate urbanization and deforestation, creating sites favourable for the breeding of filarial vectors and unsanitary conditions, water pollution with organic matters etc., are reduced below the threshold level, we will be highly benefited. Understandings of the factors related to natural phenomena of control of filariasis narrated in this article may help to adopt effective control strategies.


Lymphatic filariasis, caused by Wuchereria bancrofti, Brugia malayi and B. timori is a major public health problem of the tropics and subtropics. According to the Expert Committee on Filariasis, 905 million people were at risk of lymphatic filariasis with 90.2 millions of victims worldwide in 1984 [1] and the figures were 751.4 millions and 78.6 million in 1992 [2]. Control Programmes, with DEC and/or Ivermectin treatment [37] of the human host and vector control by different means [813] have been undertaken. At present, world wide 1.3 billion people are at risk of lymphatic filariasis (LF) infection and about 120 million people are affected in 83 countries [14]. Amongst them 45.5 million live in the Indian subcontinent and 40 million in Sub-Saharan Africa [15]. In this alarming situation, it is my aim to highlight that 'nature' itself limits filarial transmission to a great extent through different means such as by reducing vector populations, parasitic load etc otherwise the situation might have been graver. Any or more of the natural phenomena narrated below may be utilised judiciously to secure better control methods of filariasis besides methods involved in the Global Program for Elimination of Lymphatic Filariasis (GPELF) launched in 1999 [16].

The ecological factors like temperature and humidity play a significant role in filariasis transmission [17]. It is generally recognized that considerable temperature and high humidity are necessary for the survival of most vector insects but the effects of those two factors may be more vital on the development of Wuchereria larvae in its vector [18]. Bancroft [19] noticed that the microfilariae required 16–17 days in the mosquito vector to reach the infective stage and his view was corroborated by Low and James [20, 21]. Under experimental conditions, development of lymphatic filarial parasites in the mosquito takes two weeks at 27°C and 90% humidity [22]. The period of larval development varies with season [23]. At high temperature and moisture the complete cycle occupies 10–14 days but it is retarded to 6 weeks by cold [17].

Lack of synchronization between transmission season and the period of higher vector density

Experiments on the filarial vector Culex quinquefasciatus revealed that its density was found to be significantly lower (p < 0.05) in the rainy season in comparison to dry seasons (summer and winter) in different endemic areas of the tropics [2438] because their breeding places become flooded during the monsoon. On the other hand, the hot months of the rainy season and sometimes summer were found to be the high time for filarial transmission in most of the endemic areas, established by the highest infection and infectivity rates (with filarial parasites) of the vector in nature [31, 35, 3942], the shortest developmental period of the parasite in the vector [23] and highest transmission potential [43, 44] during this period of the year. The rainy season provides optimum conditions to raise the vector efficiency index (VEI) to its peak (VEI is based on rapid parasitic development, proper nursing and low parasitic damage or death) [23].

So, there is a lack of synchronization between two important factors like transmission season and the period of highest vector density, which limits transmission and keeps it at a low level.

A sharp fall of parasite load in the process of transmission

When parasite load was examined, a sharp reduction was noticed between the load of microfilariae per infected mosquito and the load of third stage infective larvae (L3) per infected mosquito (reduction is significant ; p < 0.05) in both urban and rural micro environments [43, 45]. In Fiji, Symes [46] also obtained similar results. It indicates that all the microfilariae that enter into the gastrointestinal tract of mosquito cannot survive to develop into L3 stage. Bryan et al and McGreevy et al [47, 48] reported that sometimes microfilariae are damaged by the buccopharyngeal armature of the mosquito during ingestion. Rise or fall of temperature and fall of humidity caused deformity and degeneration of a large number of filarial parasites in the mosquito body [23, 35]

Mosquitoes limit the number of migrating microfilariae by rapidly excreting them. Wharton [49] found an average of more than 100 microfilariae to be ejected in droplet from the anus of An. barbirostris fed on a cat infected with Brugia pahangi. Similar results were obtained with W. bancrofti in Cx. quinquefasciatus [50].

Hu [51] and Chandra et al [23] noted that all the microfilariae failed to escape from the midgut of the infected mosquito due to low temperature in winter in Shanghai, China and West Bengal, India respectively.

Sutherland et al [52], Yamamoto et al [53] and Christensen et al [54] reported on the defence mechanism and defence reaction of mosquito vectors to filarial worms. The growth of a high percentage of parasites is arrested in their sites of development of the vector body due to melanization and encapsulation. The antihemostatic factors present in saliva allow mosquitoes to blood-feed efficiently, but different mosquito species can differ markedly in blood feeding potency [55]. Further, the fluid consistency of ingested blood usually varies in different mosquitoes. The coagulation of ingested blood within the mid-gut also inhibits ingested pathogens from migrating out of the gut to reach the final site of development. This potential barrier to pathogen development varies significantly depending on the length of time a pathogen spends within the mid-gut. But evidently the consistency of ingested blood greatly influences both the prevalence and intensity of infection for all mosquito-borne parasites [56, 57].

Kobayashi et al studied filariasis [58] and analysed the refractory mechanisms of the mosquito Aedes aegypti to the filarial larvae Brugia malayi by means of parabiotic twinning.

The fate of larvae after leaving the proboscis is not known for W. bancrofti, but experimental data for Brugia pahangi [59, 60] revealed that during a single complete feeding 32% only of the escaping larvae succeeded in penetrating the tissues of experimental hosts. Similar results were obtained when the mosquito had a partial blood meal (31.3%) or made multiple attempts to feed (38,1%), when a single feeding attempt was unsuccessful, 10.2% of the escaping larvae succeeded in penetrating the tissues.

The most important factor in estimating the extent to which accumulation is possible is the rate of survival of immature parasites in the human. Again, data for W. bancrofti are not available, but Edeson & Buckley [61] obtained a survival to maturity of 0.13 for Brugia malayi in experimental animals, assuming a constant death rate during this immature period of 2 1/2 months, the daily mortality can be calculated as

0.13 = e -75d

When d is the instantaneous death rate per day and e is the base of natural logarithms. From the equation, e = 0.027/day, and W. bancrofti is known from unpublished WHO information to have a minimal prepatent period of 8 month and 4 days. Thus if we apply the calculated death rate, the proportion of the larvae surviving would be 0.00147 [61, 62].

So, a sharp reduction in parasite load during parasitic development in the vector, revealed from the above literature, limits transmission and keeps it at a low level.

Vector mortality

Numbers of Cx. quinquefasciatus carrying microfilariae, first stage, second stage and third stage larvae of W. bancrofti in nature gradually decreased in both urban and rural areas [43, 45]. It is an indication that all the mosquitoes (initially infected with microfilariae) cannot survive the period required for the development of microfilariae into third stage infective larvae. Different investigators recorded varied daily mortality rate of Cx. quinquefasciatus from 14% to as much as 47% in different parts of the world [35, 6370]. Almost all the authors, who worked on the vector infection and infectivity of different filarial vectors of different parts of the world [43, 45, 71] recorded significantly higher (p < 0.05) infection rate than that of infectivity rate of a particular endemic area, which is another indication of substantive vector mortality in a given period.

When presumptive mortality rate [72] of Cx. quinquefasciatus (collected from both urban and rural areas) between two successive gonotrophic cycles was determined, a high percentage of mortality of vector population was observed between two successive gonotrophic cycles. A high mortality between two successive gonotrophic cycles caused considerable reduction of vector as well as parasite population naturally.

Most of the mosquitoes carrying microfilariae were found to be nulliparous (yet to lay first batches of eggs) i.e. took microfilariae during their first blood meal when parity status was determined by Polovodova's method [73]. Pentaparous mosquito containing microfilariae proves that they may also be infected during their sixth blood meal but with the increase of age of mosquitoes, new infection with microfilariae decreased [74]. So, natural vector mortality during the period required for the development of microfilariae into third stage infective larvae is indicative of reduction in transmission.

Other bearings of natural control

Moreover, Wuchereria spp., which causes the major global burden (106.2 million out of 119.1 million), is not a zoonotic parasite i.e. man is the only known definitive host and there is no other reservoir. Except for a mosquito bite, there is no other mode of transmission. Though congenital microfilaremia has been reported [75, 76], it is of no significance. Microfilariae transmitted by blood transfusion may survive and circulate up to very limited number of days and do not develop into adult worms [17]. It can be shown in principle that there are critical densities of host and vector below which the parasite population cannot be maintained and that these critical densities are most important for parasites in which the sexes are separate [77]. This is true for all nematodes, as their sexes are separate, and here specifically for Wuchereria and Brugia. Multiple bites by infective mosquitoes are required for effective transmission. The WHO Filariasis Research Unit in Rangoon estimated that an average of around 15,500 bites by infective mosquitoes is necessary to produce 1 case of microfilaremia [62]. The major vector of nocturnally periodic Wuchereria (Cx. quinquefasciatus) breeds only in man-made polluted water and Mansonioides, vectors of Brugia breed in water bodies infested with certain preferred weeds (Pistia, Eichornia, Lemna) only [78]. At the same time they cannot oviposit in water bodies infested with ferns like Azolla, Salvinia etc [78]. So, vast water bodies, which are free of, preferred weeds or infested with Azolla or Salvinia do not favour breeding of Brugia vectors.

According to Dreyer et al factors associated with adult worm longevity are unknown [79]. They concluded that survival of adult W. bancrofti is inversely associated with transmission intensity.

Snow and Michael provided clear evidence for the existence of microfilarial density-dependence in the process of transmission for all the three major bancroftian filariasis transmitting mosquito vectors [80]. The regulation of mf uptake varied significantly between the vector genera, being weakest in Culex, stronger in Aedes and most severe and occurring at significantly lower human mf loads in Anopheles mosquitoes. It indicates lower intensities of transmission in the vast endemic areas where Culex acts as vector.

Dissanayake showed that development of adenolymphangitis and lymphoedema was strongly associated with amicrofilaraemic infection [81]. In contrast, microfilaraemic individuals are more likely to remain microfilaraemic without developing clinical lymphatic disease. It is concluded that asymptomatic microfilaraemia and amicrofilaraemic clinical disease are independent outcomes of W. bancrofti infection and are not sequential events of progressive infection. This indicates that most of the microfilaraemics do not develop symptoms and morbidity. Therefore, all these mechanisms have a natural bearing in limiting transmission.


Collectively, 'nature' plays a great role in limiting filarial transmission throughout the way of its transmission dynamics. Those people who are close to nature, such as, tribal peoples (they live in small rural set up isolated from urban areas and devoid of indiscriminate urbanization) in the developing countries are safe to a large extent from the menace of filariasis partly due to their cultural practices (they keep their courtyards and surroundings very neat and clean, without any ditches or mosquitogenic sources) [8284]. So, we can avail ourselves the blessings of the bearing of natural control of filariasis to a greater extent if manipulations on nature are reduced. One basic point of Millennium Development Goal [85] i,e. 'Respect to nature' is relevant in this context.

Filarial transmission can be reduced through man-made interventions that include source reduction i.e. reduction of mosquito larval habitats, use of natural predators, application of larvicides and adulticides of biological and chemical origins. Using these methods alone or in combination has proved helpful in regulating vector population, but to a limited extent. Emphasizing biological resources and products that would keep the vector population below the threshold level in framing strategies for regulating filarial transmission is highly required. Biological resources or products will not interfere with the natural regulation of transmission. The target points for man-made control of filariasis during transmission are restricted to vector mosquitoes, while nature imparts a regulatory effect on both the vectors and the filarial worms in the vectors. Therefore, the processes limiting filarial transmission naturally, needs to be given priority to frame effective control strategies. For instance, a record or a monitoring of the abundance of the vector population and its seasonality can be used as a background to determine the time of control operation.

As filarial vector density increases in the dry months in many endemic areas [2438], larvicides and adulticides (preferably of biological origin) may be applied just before dry season. At the same time larval predators may also be introduced in the larval habitats where such predators are absent at the onset of dry season. On the other hand, elimination of aquatic weeds that facilitate breeding of Mansonioides mosquitoes [78] mechanically or by using weedivorous fishes be done when they grow well in the wet months.

It is known that reappearance of microfilariae or recurrence of microfilaremia occurs after certain period of time in certain percentage of single dose DEC treated microfilaremics [45, 86] and low-density microfilaremia has an important role in transmitting filariasis [87]. Thus to desynchronise the period of recurrence in microfilaremia and the period of effective transmission and also to reduce overall transmission, yearly single dose mass DEC treatment (under GPELF) can be given just before monsoon when transmission occurs very effectively [23, 31, 35, 3944]. Proper measures can be adopted to avoid bites of Cx. quinquefasciatus during the peak period of filarial transmission in a 24-hour period i.e. the 3rd quadrant of night (12 mid night to 3 a.m.) [88]. Other target points are to reduce indiscriminate urbanization and deforestation, creating mosquitogenic sites and unsanitary conditions, water pollution with organic matters etc. below the threshold level.


  1. 1.

    WHO Report of the Expert Committee on Filariasis (IVth): Technical Report Series 702. 1984, 7-8.

    Google Scholar 

  2. 2.

    WHO Report of the Expert Committee on Filariasis (Vth): Lymphatic filariasis: The disease and its control. Technical Report Series 821. 1992, 1-2.

    Google Scholar 

  3. 3.

    Cartel JL, Nguyen NL, Spiegel A, Moulia-Pelat JP, Plichart R, Martin PMV, Manuellan AB, Lardeux F: Wuchereria bancrofti infection in human and mosquito populations of a Polynesian village ten years after interruption of mass chemoprophylaxix with diethylcarbamazine. Trans R Soc Trop Med Hyg. 1992, 86: 414-416. 10.1016/0035-9203(92)90245-8.

    CAS  Article  PubMed  Google Scholar 

  4. 4.

    Cartel JL, Moulia-Pelat JP, Glaziou Ph, Nguyen NL, Chanteau S, Roux JF, Spiegel A: Microfilariae recurrence in Polynesian Wuchereria bancrofti carriers treated with repeated single doses of 100 ug/kg of ivermectin. Trans R Soc Trop Med Hyg. 1993, 87: 478-480. 10.1016/0035-9203(93)90046-S.

    CAS  Article  PubMed  Google Scholar 

  5. 5.

    Shaoqing Z, Feng C, Webber R: A successful control programme for lymphatic filariasis in Hubei, China. Trans R Soc Trop Med Hyg. 1994, 88: 510-512. 10.1016/0035-9203(94)90140-6.

    Article  Google Scholar 

  6. 6.

    Bockarie MJ, Alexander NDE, Hyun P, Dimber Z, Bockarie F, Ibam E, Alpers MP, Kazura JW: Randomised community-based trial on annual single-dose diethylcarbamazine with or without ivermectin against Wuchereria bancrofti infection in human beings and mosquitoes. Lancet. 1998, 351 (9097): 162-168. 10.1016/S0140-6736(97)07081-5.

    CAS  Article  PubMed  Google Scholar 

  7. 7.

    Reuben R, Rajendran R, Sunish IP, Mani TR, Tewari SC, Hiriyan J, Gajanana A: Annual single dose diethylcarbamazine (DEC) plus ivermectin (IVR) for control of bancroftian filariasis: comparative efficacy with and without vector control. Ann Trop Med Parasit. 2001, 95: 361-378. 10.1080/00034980120065796.

    CAS  Article  PubMed  Google Scholar 

  8. 8.

    Chandra G, Bhattacharjee I, Ghosh A, Chatterjee SN: Mosquito control by larvivorous fishes – a review. Indian J Med Res. 2008, 127: 13-27.

    CAS  PubMed  Google Scholar 

  9. 9.

    Chatterjee SN, Ghosh A, Chandra G: Eco-friendly control of mosquito larvae by Brachytron pratense nymph. J Environ Health. 2007, 69 (8): 44-48.

    CAS  PubMed  Google Scholar 

  10. 10.

    Corbet PS: Use of odonate larvae for biocontrol of insect pests. Agrion. 2000, 4: 22-27.

    Google Scholar 

  11. 11.

    Aditya G, Bhattacharyya S, Kundu N, Saha GK, Raut SK: Predatory efficiency of the water bug Sphaerodema annulatum on mosquito larvae (Culex quinquefasciatus) and its effect on adult emergence. Bioresource Technology. 2004, 95: 169-172. 10.1016/j.biortech.2004.02.007.

    CAS  Article  PubMed  Google Scholar 

  12. 12.

    Castillo C, Scorza J: Evaluating the impact of a residual application of an asporogenous formulation of Bacillus thuriengiensis on mosquitoes in breeding sites. J Am Mosq Control Assoc. 1999, 15: 408-409.

    Google Scholar 

  13. 13.

    Ansari MA, Sharma VP, Mittal PK, Razdan RK, Batra CP: Evaluation of Bacillus sphaericus to control breeding of malaria vectors. IIndian J Malariol. 1989, 26 (1): 25-31.

    CAS  Google Scholar 

  14. 14.

    World Health Organization: Global Program to Eliminate Lymphatic Filariasis. Wkly Epidemiol Rec. 2006, 81 (22): 221-232.

    Google Scholar 

  15. 15.

    World Health Organization: Report of a Consultative Meeting, Lymphatic Filariasis Infection and Disease Control Strategies. TDR/CTD/FIL/PENANG/. 1994, 1: 1-2.

    Google Scholar 

  16. 16.

    Molyneux DH, Zagaria N: Lymphatic filariasis elimination: progress in global program development. Ann Trop Med Parasitol. 2002, 96 (Suppl 2): 15-40. 10.1179/000349802125002374.

    Article  Google Scholar 

  17. 17.

    Manson-Bahr PEC, Bell DR:Manson's Tropical Disease. ELBS Pub. 2003,

    Google Scholar 

  18. 18.

    Nelson CG: Factors influencing the development and behaviour of filarial nematodes in their arthropodan hosts. Second Symposium of the British Society for Parasitology. Host-parasite Relationships in Invertebrate Hosts. Edited by: Angela ER-Taylor. 1964, Blackwell Scientific publications; Oxford, 74-119.

    Google Scholar 

  19. 19.

    Bancroft TL: On the metamorphosis of the young form of Filaria bancrofti Cobb. Journal Proceedings Royal Society of New South Wales. 1899, 82: 62-65.

    Google Scholar 

  20. 20.

    Low GC: A recent observation on Filaria nocturna in Culex: Probable mode of infection of man. Brit Med J. 1900, I: 1456-1460.

    Article  Google Scholar 

  21. 21.

    James SP: On the metamorphosis of the Filaria sanguinis hominis in mosquito. Brit Med J. 1900, II: 533-536.

    Google Scholar 

  22. 22.

    Cheng TC: General Parasitology. 1986, Academic Press, Inc. Orlando, Florida

    Google Scholar 

  23. 23.

    Chandra G, Chatterjee SN, Banerjee BD, Majumdar G: Effect of seasonal variations on the development of Wuchereria larvae in Culex quinquefasciatus. Basic Appl Biomed. 1997, 5: 21-24.

    Google Scholar 

  24. 24.

    De SK, Chandra G: Studies on the filariasis vector-Culex quinquefasciatus at Kanchrapara, West Bengal, India. Indian J Med Res. 1994, 99: 255-258.

    CAS  PubMed  Google Scholar 

  25. 25.

    Knowles R, Basu BC: Mosquito prevalence and mosquito borne diseases in Calcutta city. Rec Mal Surv Ind. 1934, 4: 291-320.

    Google Scholar 

  26. 26.

    Rahman J, Singh MV, Gujral JS: Investigation of filariasis problem in Ballia town (Uttar Pradesh). Indian J Malariol. 1957, 11: 163-167.

    CAS  PubMed  Google Scholar 

  27. 27.

    Rao TR, Rajagopalan PK: Observations on mosquitoes of Poona district, India with special reference to their distribution, seasonal prevalence and the biology of the adults. Indian J Malariol. 1957, 11: 1-54.

    Google Scholar 

  28. 28.

    Varma BK, Dass NL, Sinha VP: Studies on the incidence and transmission of filariasis in Bhagalpur town (Bihar). Indian J Malariol. 1961, 15: 185-194.

    CAS  PubMed  Google Scholar 

  29. 29.

    Das UP, Hati AK, Chowdhury AB: Nocturnal man – biting mosquitoes of urban and rural areas. Bull Cal Sch Trop Med. 1971, 19: 80-83.

    CAS  Google Scholar 

  30. 30.

    Rao CK, Dutta KK, Sundaram RM, Ramprasad K, Rao JS, Venkatanarayana M, Nath VVN, Rao PK, Rao Ch K, Das M, Sharma SP: Epidemiological studies on bancroftian filariasis in East Godavari district (A.P.): baseline fialriometric indices. Indian J Med Res. 1980, 71: 712-720.

    CAS  PubMed  Google Scholar 

  31. 31.

    Dash AP, Tripathi N, Hazra RK: Bionomics and vectorial capacity of mosquitoes in Puri district, Orissa. Proceedings of the Second Symposium on vector and vector borne diseases. 1988, 90-100.

    Google Scholar 

  32. 32.

    Dhar SK, Das N, Srivastava BN, Menon PKN, Basu PC: Seasonal prevalence, resting habits, host preference and filarial infection of Culex fatigans in Rajamundry town, A.P. Bull Indian Soc Mal and other Commun Dis. 1968, 5: 74-87.

    Google Scholar 

  33. 33.

    Chandra G, Banerjee A, Hati AK: Seasonal prevalence of Culex quinquefasciatus in an urban and a rural area of West Bengal. Bull Cal Sch Trop Med. 1993, 41: 10-11.

    Google Scholar 

  34. 34.

    Nanda DK, Singh MV, Chand D: Study of the effect of climate on the density of Culex fatigans and the development of the filarial parasite in it. Indian J Mal. 1962, 16: 313-320.

    CAS  Google Scholar 

  35. 35.

    Rozeboom LE, Bhattacharya NC, Gillotra SK: Observations of the transmission of filariasis in urban Calcutta. Am J Epidemiol. 1968, 87 (3): 616-632.

    CAS  PubMed  Google Scholar 

  36. 36.

    Joe LK, Hudojo W, Maliah SA: Filariasis survey in Rawasare district, Djakarta. Indian J Mal. 1960, 14: 339-352.

    Google Scholar 

  37. 37.

    Service MW: The ecology of the mosquitoes of Northern Guiena Savannah of Nigeria. Bull Ent Res. 1963, 54: 601-630.

    Article  Google Scholar 

  38. 38.

    Ogunba EO: Observations on Culex pipens fatigans in Ibadan, Western Nigeria. Ann Trop Med Parasit. 1971, 65: 399-402.

    CAS  PubMed  Google Scholar 

  39. 39.

    Aslamkhan M, Wolfe MS: Bancroftian filariasis in two villages in Dinajpur district East Pakistan II Entomological investigations. Am J Trop Med Hyg. 1972, 21: 30-37.

    CAS  PubMed  Google Scholar 

  40. 40.

    Ghosh SN, Hati AK: House frequenting mosquitoes of West Bengal and Calcutta: Detection of filarial parasites in Anopheles and Culex sp. Bull Cal Sch Trop Med. 1966, 14: 9-10.

    CAS  Google Scholar 

  41. 41.

    Heisch RB, Nelson GS, Furlong M: Studies on fialriasis in East Africa I. Filariasis on the island of Pate Kenya. Trans Roy Soc Trop Med Hyg. 1959, 53: 41-53. 10.1016/0035-9203(59)90082-3.

    CAS  Article  PubMed  Google Scholar 

  42. 42.

    Varma BK, Sinha VP, Dass NL: Filariasis in Sultanganj and its suburbs (Bihar). Bull Nat Soc Indian Mal and other Mos Borne Dis. 1960, 8: 149-152.

    Google Scholar 

  43. 43.

    Hati AK, Chandra G, Bhattacharyya A, Biswas D, Chatterjee KK, Dwibedi HN: Annual transmission potential of bancroftian filariasis in an urban and a rural area of West Bengal, India. Am J Trop Med Hyg. 1989, 40 (4): 305-307.

    Google Scholar 

  44. 44.

    Chandra G, Rudra SK: Comparative studies on man-biting population of filarial vector Cx. quinquefasciatus (Diptera: Culicidae) between tribal and non-tribal areas of Bankura district West Bengal India. Bul Pen Kesh. 2006, 34: 1-7.

    Google Scholar 

  45. 45.

    Chandra G, Chatterjee SN, Das S, Sarkar N: Lymphatic filariasis in the coastal areas of Digha, West Bengal, India. Trop Doct. 2007, 37 (3): 136-139. 10.1258/004947507781524737.

    CAS  Article  PubMed  Google Scholar 

  46. 46.

    Symes CB: Filarial infections in mosquitoes in Fiji. Trans Roy Soc Trop Med Hyg. 1955, 49: 280-284. 10.1016/0035-9203(55)90071-7.

    CAS  Article  PubMed  Google Scholar 

  47. 47.

    Bryan JH, Oothman P, Andrews BJ, McGreevy PB: Effect of pharyngeal armature of mosquitoes on microfilariae of Brugia pahangi. Trans Roy Soc Trop Med Hyg. 1974, 68: 14-19. 10.1016/0035-9203(74)90241-7.

    CAS  Article  PubMed  Google Scholar 

  48. 48.

    McGreevy PB, Bryan JH, Oothuman P, Kolstrup N: The lethal effects of the cibarial and pharyngeal armatures of mosquitoes on microfilariae. Trans R Soc Trop Med Hyg. 1978, 72: 361-368. 10.1016/0035-9203(78)90128-1.

    CAS  Article  PubMed  Google Scholar 

  49. 49.

    Wharton RH: The biology of Mansonia mosquitoes in relation to the transmission of filariasis in Malaya. Bull Inst Med Res. 1962, 11: 114-122.

    Google Scholar 

  50. 50.

    Jordan P, Goatly KD: Brancroftian filanasis in Tanganyika ; a quantitative study on the uptake, fate and development of Wuchereria bancrofti. Ann Trop Med Parasit. 1962, 56: 173-181.

    Google Scholar 

  51. 51.

    Hu SMK: Observation on the development of filarial larvae during the winter season in Shanghai region. Am J Hyg. 1939, 29: 67-74.

    Google Scholar 

  52. 52.

    Sutherland DR, Christensen BM, Forton KF: Defence reactions of mosquitoes to filarial worms: Role of the microfilarial sheath in the response of mosquitoes to inoculated Brugia pahangi microfilariae. J Inver Path. 1984, 44: 275-281. 10.1016/0022-2011(84)90025-9.

    CAS  Article  Google Scholar 

  53. 53.

    Yamamoto H, Kobayashi M, Ogura N, Tsuruoka H, Chigusa Y: Studies on filariasis. VI. The encapsulation of Brugia malayi and B. pahangi larva in the mosquito, Armigeres subalbatus. Jpn J Sanit Zool. 1985, 36: 1-6.

    Google Scholar 

  54. 54.

    Christensen BM, Sutherland DR, Gleason LN: Defense reactions of mosquitoes to filarial worms: comparative studies on the response of three different mosquitoes to inoculated Brugia pahangi and Dirofilaria immitis microfilariae. J Invertebr Pathol. 1984, 44: 267-274. 10.1016/0022-2011(84)90024-7.

    CAS  Article  PubMed  Google Scholar 

  55. 55.

    Stark KR, James AA: Anticoagulants in vector arthropods. Parasitol Today. 1996, 12: 430-437. 10.1016/0169-4758(96)10064-8.

    CAS  Article  PubMed  Google Scholar 

  56. 56.

    Kartman L: Factors influencing infection of the mosquito with Dirofilaria immitis (Leidy, 1856). Exp Parasitol. 1953, 2: 27-78. 10.1016/0014-4894(53)90005-8.

    Article  Google Scholar 

  57. 57.

    Beerntsen BT, James AA, Christensen BM: Genetics of Mosquito Vector Competence. Microbiol Mol Biol Rev. 2000, 64: 115-137. 10.1128/MMBR.64.1.115-137.2000.

    PubMed Central  CAS  Article  PubMed  Google Scholar 

  58. 58.

    Kobayashi M, Ogura N, Yamamoto H: Studies of filariasis X: a trial to analyse refractory mechanisms of the mosquito Aedes aegypti to the filarial larvae Brugia malayi by means of parabiotic twinning. Dokkyo J Med Sci. 1986, 13: 61-67.

    Google Scholar 

  59. 59.

    Ewert A, Ho BC: The fate of Brugia pahangi larvae immediately after feeding by infective vector mosquitoes. Trans Roy Soc Trop Med Hyg. 1967, 61: 659-662. 10.1016/0035-9203(67)90129-0.

    CAS  Article  PubMed  Google Scholar 

  60. 60.

    Ho BC, Ewert A: Experimental transmission of filarial larvae in relation to feeding behaviour of the mosquito vectors. Trans Roy Soc Trop Med Hyg. 1967, 61: 663-666. 10.1016/0035-9203(67)90130-7.

    CAS  Article  PubMed  Google Scholar 

  61. 61.

    Edeson JFB, Buckley JJC: Studies on filariasis in Malaya: on the migration and rate of growth of Wuchereria malayi in experimentally infected cats. Ann Trop Med Parasit. 1959, 53: 113-19.

    CAS  PubMed  Google Scholar 

  62. 62.

    Hairston NG, De Meillon B: On the inefficiency of transmission of Wuchereria bancrofti from mosquito to human host. Bull World Health Organ. 1968, 38 (6): 935-941.

    PubMed Central  CAS  PubMed  Google Scholar 

  63. 63.

    Laurence BR: Natural mortality in two filarial vectors. Bull Wld Hlth Org. 1963, 28: 229-234.

    CAS  Google Scholar 

  64. 64.

    Samarawickarema WA: A study of the age composition of natural population of Culex pipiens fatigans (Wiedemann) in relation to the transmission of Filariasis due to Wuchereria bancrofti (Cobbold) in Ceylon. Bull Wld Hlth Org. 1967, 37: 117-137.

    Google Scholar 

  65. 65.

    de Meillon B, Grab B, Sebastian A: Evaluation of Wuchereria bancrofti infection in Culex pipiens fatigans in Rangoon, Burma. Bull World Health Organ. 1967, 36 (1): 91-100.

    PubMed Central  CAS  PubMed  Google Scholar 

  66. 66.

    Self LS, Vsman S, Sajidiman H, Partons F, Nelson MJ, Pant CP, Suzuki T, Mc chfudin H: A multidisciplinary study on bancroftian filariasis in Djakarta. Trans Roy Soc Trop Med Hyg. 1978, 72: 581-587. 10.1016/0035-9203(78)90006-8.

    CAS  Article  PubMed  Google Scholar 

  67. 67.

    Birley MH, Rajagopalan PK: Estimation of the survival and bitting rates of Culex quinquefasciatus (Diptera:Culicidae). J Med Entomol. 1981, 18 (3): 181-186.

    CAS  Article  PubMed  Google Scholar 

  68. 68.

    Holmes PR: A Study of Population changes in adult Culex quinquefasciatus say (Diptera:Culicidae) during a mosquito control programme in Dubai, United Arab Emirates. Ann Trop Med Parasit. 1986, 80: 107-116.

    CAS  PubMed  Google Scholar 

  69. 69.

    Chandra G, Banerjee A, Hati AK: Age determination of Culex quinquefasciatus of a rural area. Bull Cal Sch Trop Med. 1992, 40: 18-19.

    Google Scholar 

  70. 70.

    Chandra G, Seal B, Hati AK: Age composition of filarial vector Culex quinquefasciatus (Diptera: Culicidae) in Calcutta. Bull Ent Res. 1996, 86: 223-226.

    Article  Google Scholar 

  71. 71.

    Hawking F: Distribution of filariasis in Tanganyika territory, East Africa. Ann Trop Med Parasit. 1940, 34: 107-119.

    Google Scholar 

  72. 72.

    Giles MT, Wilkes TJ: A study of the age composition of popultions of Anopheles gambiae (Giles) and Anopheles funestus (Gilles) in North Eastern Tanzania. Bull Ent Res. 1965, 56: 237-262.

    Article  Google Scholar 

  73. 73.

    Polovadova VP: The determination of the physiological age of female Anopheles by the number of gonotrophic cycle completed. Meditsinskaya Parazi totogiya Parazitarnye Bokzni. 1949, 18: 352-355.

    Google Scholar 

  74. 74.

    Chandra G: Correlation between infected filarial vectors and their parity status. Environ Ecol. 1994, 12: 694-695.

    Google Scholar 

  75. 75.

    Raghavan NGS: Congenital filariasis. Bull Nat Soc Indian Mal Mosq Dis. 1958, 6: 147-154.

    Google Scholar 

  76. 76.

    Eberhard ML, Hitch WL, McNeeley DF, Lammie PJ: Tranplacental transmission of Wuchereria bancrofti in Haitian women. J Parasitol. 1963, 79 (1): 62-66. 10.2307/3283278.

    Article  Google Scholar 

  77. 77.

    Hairston NG: Population ecology and epidemiological problems. Edited by: Wolstenholme GEW, O'Connor M. 1962, Bilharziasis, London, Churchill, 36-62. (Ciba Foundation Symposium)

    Google Scholar 

  78. 78.

    Chandra G, Ghosh A, Biswas D, Chatterjee SN: Host plant preference of Mansonia mosquitoes. J Aquatic Plant Management. 2006, 44: 142-144.

    Google Scholar 

  79. 79.

    Dryer G, David A, Joaquim N: Does longevity of adult Wuchereria bancrofti increase with decreasing intensity of parasite transmission? Insights from clinical observations. Trans Roy Soc Trop Med Hyg. 2005, 99: 883-92. 10.1016/j.trstmh.2005.05.006.

    Article  Google Scholar 

  80. 80.

    Snow LC, Michael E: Transmission dynamics of lymphatic filariasis: density-dependence in the uptake of Wuchereria bancrofti microfilariae by vector mosquitoes. Med Vet Entomol. 2002, 16: 409-23. 10.1046/j.1365-2915.2002.00396.x.

    CAS  Article  PubMed  Google Scholar 

  81. 81.

    Dissanayake S: Wuchereria bancrofti filariasis, asymptomatic microfilaraemia does not progress to a microfilaraemic lymphatic disease. Int J Epidemiology. 2001, 30: 394-399. 10.1093/ije/30.2.394.

    CAS  Article  Google Scholar 

  82. 82.

    Govardhini P, Chand G: Preliminary findings from an epidemiological study of Bancroftian filariasis in Guna District, M.P. Indian J Com Med. 1994, 19: 7-11.

    Google Scholar 

  83. 83.

    Rudra SK, Chandra G: Bancroftian filariasis in tribal population of Bankura district, West Bengal India. Jap J Trop Med Hyg. 1998, 26: 109-112.

    Article  Google Scholar 

  84. 84.

    Rudra SK, Chandra G: Comparative epidemiological studies on lymphatic filariasis, between tribal and non-tribal populations of Bankura district, West Bengal, India. Ann Trop Med Parasit. 2000, 94: 365-372.

    CAS  PubMed  Google Scholar 

  85. 85.

    The Millennium Development Goals Report 2006. United Nations New York, 1-32.

  86. 86.

    Cartel JL, Nguyen NL, Spiegel A, Moulia-Pelat JP, Plichart R, Martin PMV, Manuellan AB, Lardeux F: Wuchereria bancrofti infection in human and mosquito populations of a Polynesian village ten years after interruption of mass chemoprophylaxix with diethylcarbamazine. Trans R Soc Trop Med Hyg. 1992, 86: 414-416. 10.1016/0035-9203(92)90245-8.

    CAS  Article  PubMed  Google Scholar 

  87. 87.

    Jayasekera N, Kalpage KSP, De Silva CSS: The significance of low density microfilaremia in the transmission of Wuchereria bancrofti by Culex (Culex) quinquefasciatus Say in Sri Lanka. Trans R Soc Trop Med Hyg. 1991, 85: 250-254. 10.1016/0035-9203(91)90044-Y.

    CAS  Article  PubMed  Google Scholar 

  88. 88.

    Chandra G: Peak period of filarial transmission. Am J Trop Med Hyg. 1995, 53: 378-379.

    CAS  PubMed  Google Scholar 

Download references

Author information



Corresponding author

Correspondence to Goutam Chandra.

Rights and permissions

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Reprints and Permissions

About this article

Cite this article

Chandra, G. Nature limits filarial transmission. Parasites Vectors 1, 13 (2008).

Download citation


  • Blood Meal
  • Ivermectin
  • Lymphatic Filariasis
  • Filariasis
  • Filarial Parasite