A Polymerase Chain Reaction Assay for the Detection of Brugia Malayi in Blood

Lizotte, Michelle R.; Supali, Taniawati; Partònò, F; Williams, Steven A.

doi:10.4269/ajtmh.1994.51.314

Cited by 90 publications

(49 citation statements)

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“…18 The simple DNA extraction procedure should greatly facilitate establishment of the PCR approach for monitoring infected snails during early prepatency. Furthermore, collection of snails in EDTA was shown (Hamburger J and others, unpublished data) as suitable for long-term preservation of the DNA at ambient temperature, as has been previously shown with blood 19 and sputum. 18 Since collection of snails is simple and can be done by village workers, 20 one can envisage a logistically convenient separation of snail collection and storage from the high technology required for their testing by PCR in central laboratories.…”

Section: Discussionmentioning

confidence: 99%

A polymerase chain reaction assay for detecting snails infected with bilharzia parasites (Schistosoma mansoni) from very early prepatency.

Hamburger¹,

He-Na²,

Xin³

et al. 1998

Am J Trop Med Hyg

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Abstract. In the present study, we adapted a polymerase chain reaction (PCR) assay, previously shown by us to be very sensitive for detecting cercariae in water, for the sensitive detection of Schistosoma mansoni DNA in infected snails from early prepatency. Polymerase chain reaction primers were designed based on the 121-basepair highly repeated sequence we previously identified in the genome of S. mansoni. The DNA was prepared from the snails by a simple alkaline extraction procedure, and the PCR assay enabled a clear differentiation between infected and normal snails. Infected snails were detected as early as one day after penetration of a single miracidium. The high sensitivity of the test enabled identification of a single infected snail even when its DNA was pooled with material from up to 99 uninfected snails, thus demonstrating the possibility of mass diagnosis in pools of snails. The assay has the potential for large-scale determination of prepatent infection prevalence in snails, thus offering new possibilities for the evaluation of schistosomiasis transmission and for schistosomiais control, as discussed.Schistosomiasis, is caused in humans by three main species of blood flukes (Schistosoma mansoni, S. haematobium, and S. japonicum) and is transmitted by freshwater snails. It continues to plague many developing countries in the tropics 1 with an estimated 200 million infected people worldwide.Freshwater snails, intermediate hosts of schistosomes, become infected by larvae (miracidia) released from schistosome eggs that reach the water with excreta. After several weeks of asexual multiplication within the snail's tissues, larvae infective to humans by active penetration through the skin (cercariae), are released into the water. Snail infection and contact patterns of humans with water infested with cercariae are important factors in the transmission of schistosomiasis, and risk of infection is normally estimated by detecting infected intermediate hosts in sites where humans come in contact with water. 2 Infection rates in field populations of snails are routinely determined by searching for cercariae shed from snails with patent infection. 3 In contrast, prepatent infections, which can constitute a significant proportion of infected snails populations, 4 are not determined routinely because of a lack of a suitable method. Microscopic examination of crushed snails in search of developing cercariae and intramolluscan-multiplying larvae (the sporocysts) 5 is sometimes used for this purpose but is highly inaccurate at early prepatency, and unsuitable for routine large-scale screening of snail populations. 4 Another approach is to examine nonshedding field snails maintained for several weeks in the laboratory for protracted shedding. However, this method is time-consuming, it cannot be done routinely on a large scale, and it can be highly inaccurate if snails mortality is high. The omission of data on prepatent infections leaves out important information for the evaluation and mathematical modeling of trans...

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Section: Discussionmentioning

confidence: 99%

A polymerase chain reaction assay for detecting snails infected with bilharzia parasites (Schistosoma mansoni) from very early prepatency.

Hamburger¹,

He-Na²,

Xin³

et al. 1998

Am J Trop Med Hyg

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“…In these cases, L. loa specific circulating DNAs released from dead filariae (since they were negative by microscopy) were detected by the assay. The possibility of detecting circulating DNA or 'free DNA' released from dead filariae by PCR has been previously suggested in lymphatic filariasis Brugia malayi (Lizotte et al 1994). The 51 individuals who were PCR-negative represent the non infected individuals and the putative resistant subjects.…”

Section: Discussionmentioning

confidence: 99%

“…were developed for species-specific detection of filarial parasites in blood samples from infected individuals: Brugia malayi (Lizotte et al 1994); Wuchereria bancrofti (Zhong et al 1996;Williams et al 1996); Loa loa (Touré et al 1997a) and even in mosquito vectors (Chanteau et al 1994;Nicolas et al 1996). The repeat-3 region (15r3) of the gene coding for L. loa 15 kD polyprotein has been described as being species-specific (Touré et al 1997a).…”

Section: Tmih260mentioning

confidence: 99%

Human occult loiasis: field evaluation of a nested polymerase chain reaction assay for the detection of occult infection

Touré

Mavoungou

Kassambara

et al. 1998

Tropical Med Int Health

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SummaryA nested polymerase chain reaction (nested PCR) assay, targeted on the repeat 3 region (15r3) of the gene coding for a Loa loa 15 kD polyprotein, was developed to detect L. loa infection. The assay has a sensitivity of 95% and is 100% specific with regard to sympatric filarial parasites: Mansonella perstans, Onchocerca volvulus and Wuchereria bancrofti. In this field study in a mixed filarial (L. loa and M. perstans) endemic region of Gabon, 157 L. loa amicrofilaraemic blood samples (AMF; diagnosed by leucoconcentration followed by standard microscopic examination) from the residents from four villages were screened by the 15r3-nested PCR assay. The assay detected 106 occult infected subjects among the 157 AMF individuals (68%), including 59 of 87 adults (68%) and 47 of 70 children (67%). In each village the prevalence of occult infection was, respectively, 38%, 52%, 79% and 80% for Moyabi, Djoutou, NЈdjokaye and Okoumbi. The annual transmission potential (ATP) of loiasis has been estimated to be 250 infective larvae (L 3) per man per year for Moyabi and Djoutou, 1800 for NЈdjokaye and 43000 L3/man/year for Okoumbi. This implies a correlation between occult infection of loiasis and the intensity of transmission. By contrast, the prevalence of L. loa microfilariae was 21% for Okoumbi, 22% for NЈdjokaye and 19% for Djoutou and Moyabi. These results show that the prevalence of loiasis in this region of Gabon is higher than previously described by standard microscopic examination and that the application of this assay will be significant in the development of control strategies for loiasis.

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“…4,5 Various sensitive polymerase chain reaction (PCR) assays have been established to detect W. bancrofti or B. malayi DNA in the human host or the mosquito vector. [6][7][8][9][10][11][12][13][14][15] Inhibition of a PCR, which may occur in both samples obtained from the mosquito vector and samples from the human host, is a common problem during DNA amplification and makes the standardization of PCR tests difficult. 16 Therefore, DNA constructs were used as internal standards (controls) in the PCR to avoid false-negative results in a diagnostic PCR.…”

mentioning

confidence: 99%

Detection of DNA of nocturnally periodic Brugia malayi in night and day blood samples by a polymerase chain reaction-ELISA-based method using an internal control DNA.

Fischer

Supali²,

Wibowo³

et al. 2000

The American Journal of Tropical Medicine and Hygiene

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Abstract. An internal control was used in a polymerase chain reaction (PCR)-ELISA-based technique to detect the Hha I repeat of the filarial parasite Brugia malayi. A single microfilaria added to 200 l of blood was reliably detected. The assay was evaluated on field samples from persons living in an area endemic for Anopheles-transmitted, nocturnally periodic B. malayi in central Sulawesi, Indonesia. Examination of night blood of 138 individuals for the presence of microfilariae by filtration revealed 44 microfilaria carriers. All microfilaria carriers were also positive in the PCR-ELISA and, in addition, 14 more samples were proven to contain parasite DNA. The sensitivity of both methods was compared on night and on day blood samples collected from 113 persons. Whereas 37 microfilaria carriers were identified by filtration of night blood, no microfilariae were observed in the corresponding day blood samples. The PCR-ELISA result was positive in all 37 night blood samples of microfilaria carriers and in an additional 13 night blood samples without microfilariae. Parasite DNA was detected in 31 day blood samples of microfilaria carriers and in 3 day blood samples of amicrofilaremic persons. Assuming a sensitivity of the PCR-ELISA on night blood of 100%, the sensitivity of night blood filtration is 74% and that of the PCR-ELISA on day blood is 68%. These data suggest that the described PCR-ELISA method is capable of detecting infections with nocturnally periodic B. malayi in day blood samples. Therefore, this method may facilitate both the identification of endemic areas and the monitoring of control programs.Lymphatic filariasis, caused by Wuchereria bancrofti and Brugia malayi, has been targeted by the World Health Organization for elimination as a public health problem by the year 2020. 1 Therefore, control programs have been or will be launched world-wide with an emphasis on communitywide treatment with diethylcarbamazine (DEC) and ivermectin or albendazole.2 To monitor the success of such intervention programs, sensitive and cost effective diagnostic tools are required. It is estimated that 115 million people are infected with W. bancrofti and about 13 million with B. malayi. 3 In Asia, 1 of 5 filarial infections is due to B. malayi and in some countries this parasite is responsible for the majority of infections. 4,5

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A Polymerase Chain Reaction Assay for the Detection of Brugia Malayi in Blood

Cited by 90 publications

References 0 publications

A polymerase chain reaction assay for detecting snails infected with bilharzia parasites (Schistosoma mansoni) from very early prepatency.

A polymerase chain reaction assay for detecting snails infected with bilharzia parasites (Schistosoma mansoni) from very early prepatency.

Human occult loiasis: field evaluation of a nested polymerase chain reaction assay for the detection of occult infection

Detection of DNA of nocturnally periodic Brugia malayi in night and day blood samples by a polymerase chain reaction-ELISA-based method using an internal control DNA.

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