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Armigeres subalbatus incriminated as a vector of zoonotic Brugia pahangi filariasis in suburban Kuala Lumpur, Peninsular Malaysia.

Muslim A, Fong MY, Mahmud R, Lau YL, Sivanandam S - Parasit Vectors (2013)

Bottom Line: Male adult worms were confirmed to be B. pahangi by the ratio length of their spicules (left spicule: right spicule).Female adult worms were confirmed by the absence of minute cuticular bosses in the tail region.The worms were further confirmed to be B. pahangi by PCR.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: In 2011, we reported occurrence of natural human infections with Brugia pahangi, a filarial worm of dogs and cats, in a surburb of Kuala Lumpur, the capital city of Malaysia. Our preliminary entomological survey at that time suggested the mosquito species Armigeres subalbatus as the vector of the zoonotic infections. In this present report, we provide biological evidence to confirm our preliminary finding.

Findings: A total of 1798 adult female Ar. subalbatus mosquitoes was caught in the vicinity of the suburb, and 1599 were dissected for the presence of filarial larvae. Sixty-two mosquitoes were positive, and 27 of these were infected with L3 larvae. The L3 were inoculated into male gerbils. Microfilariae could be detected in the gerbils 92 days post-infection. Post-mortem on the gerbils recovered adult worms in the peritoneal cavity, heart, lungs, tail and testis. Male adult worms were confirmed to be B. pahangi by the ratio length of their spicules (left spicule: right spicule). Female adult worms were confirmed by the absence of minute cuticular bosses in the tail region. The worms were further confirmed to be B. pahangi by PCR.

Conclusions: Our results showed that Ar. subalbatus was the vector for the zoonotic Brugia pahangi infections. This mosquito species should now be categorised as a medically important mosquito species in Malaysia. Its role in the transmission of zoonotic B. pahangi must therefore be considered in future studies on filarial infections.

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Related in: MedlinePlus

Identification of species based on: (A) the ratio length of spicules (left spicule:right spicule, LS:RS) in adult male, the worm was confirmed to be B. pahangi with LS:RS = 2.00:1; and (B) tail region of adult female of B. pahangi, with body cuticle devoid of minute cuticular bosses (x40).
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Figure 1: Identification of species based on: (A) the ratio length of spicules (left spicule:right spicule, LS:RS) in adult male, the worm was confirmed to be B. pahangi with LS:RS = 2.00:1; and (B) tail region of adult female of B. pahangi, with body cuticle devoid of minute cuticular bosses (x40).

Mentions: Post mortem on the gerbils was carried out 95 days post-infection. Eighteen adult worms were recovered, in which 16 were recovered in the peritoneal cavity, heart, lungs and tail of the first gerbil. Two were recovered from the testis of the second gerbil. Five of the 7 adult male worms were cleared and mounted for identification. They were confirmed to be B. pahangi by determining the ratio length of their spicules (LS:RS). The ratios of the adult male worms obtained were 2.47:1, 2.36:1, 2.38:1, 2.06:1 and 2.00:1 (Figure 1A), respectively. These ratios were within the ratio range for B. pahangi (1.80-2.50:1) which is much smaller than the ratio of B. malayi (2.90-3.80:1) [12]. The 9 adult female worms were confirmed to be B. pahangi by examining their body cuticle in the tail region. The body cuticle of B. pahangi adult female worm is devoid of the minute cuticular bosses (Figure 1B), which are only seen in female B. malayi adult worm [12].


Armigeres subalbatus incriminated as a vector of zoonotic Brugia pahangi filariasis in suburban Kuala Lumpur, Peninsular Malaysia.

Muslim A, Fong MY, Mahmud R, Lau YL, Sivanandam S - Parasit Vectors (2013)

Identification of species based on: (A) the ratio length of spicules (left spicule:right spicule, LS:RS) in adult male, the worm was confirmed to be B. pahangi with LS:RS = 2.00:1; and (B) tail region of adult female of B. pahangi, with body cuticle devoid of minute cuticular bosses (x40).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3750234&req=5

Figure 1: Identification of species based on: (A) the ratio length of spicules (left spicule:right spicule, LS:RS) in adult male, the worm was confirmed to be B. pahangi with LS:RS = 2.00:1; and (B) tail region of adult female of B. pahangi, with body cuticle devoid of minute cuticular bosses (x40).
Mentions: Post mortem on the gerbils was carried out 95 days post-infection. Eighteen adult worms were recovered, in which 16 were recovered in the peritoneal cavity, heart, lungs and tail of the first gerbil. Two were recovered from the testis of the second gerbil. Five of the 7 adult male worms were cleared and mounted for identification. They were confirmed to be B. pahangi by determining the ratio length of their spicules (LS:RS). The ratios of the adult male worms obtained were 2.47:1, 2.36:1, 2.38:1, 2.06:1 and 2.00:1 (Figure 1A), respectively. These ratios were within the ratio range for B. pahangi (1.80-2.50:1) which is much smaller than the ratio of B. malayi (2.90-3.80:1) [12]. The 9 adult female worms were confirmed to be B. pahangi by examining their body cuticle in the tail region. The body cuticle of B. pahangi adult female worm is devoid of the minute cuticular bosses (Figure 1B), which are only seen in female B. malayi adult worm [12].

Bottom Line: Male adult worms were confirmed to be B. pahangi by the ratio length of their spicules (left spicule: right spicule).Female adult worms were confirmed by the absence of minute cuticular bosses in the tail region.The worms were further confirmed to be B. pahangi by PCR.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: In 2011, we reported occurrence of natural human infections with Brugia pahangi, a filarial worm of dogs and cats, in a surburb of Kuala Lumpur, the capital city of Malaysia. Our preliminary entomological survey at that time suggested the mosquito species Armigeres subalbatus as the vector of the zoonotic infections. In this present report, we provide biological evidence to confirm our preliminary finding.

Findings: A total of 1798 adult female Ar. subalbatus mosquitoes was caught in the vicinity of the suburb, and 1599 were dissected for the presence of filarial larvae. Sixty-two mosquitoes were positive, and 27 of these were infected with L3 larvae. The L3 were inoculated into male gerbils. Microfilariae could be detected in the gerbils 92 days post-infection. Post-mortem on the gerbils recovered adult worms in the peritoneal cavity, heart, lungs, tail and testis. Male adult worms were confirmed to be B. pahangi by the ratio length of their spicules (left spicule: right spicule). Female adult worms were confirmed by the absence of minute cuticular bosses in the tail region. The worms were further confirmed to be B. pahangi by PCR.

Conclusions: Our results showed that Ar. subalbatus was the vector for the zoonotic Brugia pahangi infections. This mosquito species should now be categorised as a medically important mosquito species in Malaysia. Its role in the transmission of zoonotic B. pahangi must therefore be considered in future studies on filarial infections.

Show MeSH
Related in: MedlinePlus