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Colonization of Lutzomyia verrucarum and Lutzomyia longipalpis Sand Flies (Diptera: Psychodidae) by Bartonella bacilliformis, the Etiologic Agent of Carrión's Disease.

Battisti JM, Lawyer PG, Minnick MF - PLoS Negl Trop Dis (2015)

Bottom Line: After 48 h, B. bacilliformis transitioned from bacillus-shape to a non-motile, small coccoid form and appeared to be digested along with the blood meal in both fly species.The capacity of L. longipalpis to transmit viable B. bacilliformis from infected to uninfected meals was analyzed via interrupted feeds.This study provides significant information toward understanding colonization of sand flies by B. bacilliformis and also demonstrates the utility of L. longipalpis as a user-friendly, live-vector model system for studying this severely neglected tropical disease.

View Article: PubMed Central - PubMed

Affiliation: Division of Biological Sciences, University of Montana, Missoula, Montana, United States of America.

ABSTRACT
Bartonella bacilliformis is a pathogenic bacterium transmitted to humans presumably by bites of phlebotomine sand flies, infection with which results in a bi-phasic syndrome termed Carrión's disease. After constructing a low-passage GFP-labeled strain of B. bacilliformis, we artificially infected Lutzomyia verrucarum and L. longipalpis populations, and subsequently monitored colonization of sand flies by fluorescence microscopy. Initially, colonization of the two fly species was indistinguishable, with bacteria exhibiting a high degree of motility, yet still confined to the abdominal midgut. After 48 h, B. bacilliformis transitioned from bacillus-shape to a non-motile, small coccoid form and appeared to be digested along with the blood meal in both fly species. Differences in colonization patterns became evident at 72 h when B. bacilliformis was observed at relatively high density outside the peritrophic membrane in the lumen of the midgut in L. verrucarum, but colonization of L. longipalpis was limited to the blood meal within the intra-peritrophic space of the abdominal midgut, and the majority of bacteria were digested along with the blood meal by day 7. The viability of B. bacilliformis in L. longipalpis was assessed by artificially infecting, homogenizing, and plating for determination of colony-forming units in individual flies over a 13-d time course. Bacteria remained viable at relatively high density for approximately seven days, suggesting that L. longipalpis could potentially serve as a vector. The capacity of L. longipalpis to transmit viable B. bacilliformis from infected to uninfected meals was analyzed via interrupted feeds. No viable bacteria were retrieved from uninfected blood meals in these experiments. This study provides significant information toward understanding colonization of sand flies by B. bacilliformis and also demonstrates the utility of L. longipalpis as a user-friendly, live-vector model system for studying this severely neglected tropical disease.

No MeSH data available.


Related in: MedlinePlus

L. verrucarum at 5d post-blood meal.After 5 d B. bacilliformis colonized the competent sand fly digestive tract. As observed at 72 h following the blood meal, bacteria were found in the abdominal midgut (A-B) as well as the ileum (C-F). Images were acquired with fluorescence (GFP) or phase contrast (PC) microscopy and the magnification used is indicated under each image pair.
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pntd.0004128.g005: L. verrucarum at 5d post-blood meal.After 5 d B. bacilliformis colonized the competent sand fly digestive tract. As observed at 72 h following the blood meal, bacteria were found in the abdominal midgut (A-B) as well as the ileum (C-F). Images were acquired with fluorescence (GFP) or phase contrast (PC) microscopy and the magnification used is indicated under each image pair.

Mentions: At 5 d post-blood meal, the L. verrucarum digestive tract continued to be colonized by B. bacilliformis beyond the boundary of the AM (Fig 5). Colonization of L. longipalpis examined at this time point exhibited a significant decrease in density, where minute GFP signals, and questionably viable bacteria, were observed. One example of a questionable signal, however, was observed in the cibarium of L. longipalpis at 7 d post-blood meal (Fig 6). Thus, by 7d post-blood meal, B. bacilliformis was apparently cleared from L. longipalpis, whereas infection of L. verrucarum was quite apparent.


Colonization of Lutzomyia verrucarum and Lutzomyia longipalpis Sand Flies (Diptera: Psychodidae) by Bartonella bacilliformis, the Etiologic Agent of Carrión's Disease.

Battisti JM, Lawyer PG, Minnick MF - PLoS Negl Trop Dis (2015)

L. verrucarum at 5d post-blood meal.After 5 d B. bacilliformis colonized the competent sand fly digestive tract. As observed at 72 h following the blood meal, bacteria were found in the abdominal midgut (A-B) as well as the ileum (C-F). Images were acquired with fluorescence (GFP) or phase contrast (PC) microscopy and the magnification used is indicated under each image pair.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4593541&req=5

pntd.0004128.g005: L. verrucarum at 5d post-blood meal.After 5 d B. bacilliformis colonized the competent sand fly digestive tract. As observed at 72 h following the blood meal, bacteria were found in the abdominal midgut (A-B) as well as the ileum (C-F). Images were acquired with fluorescence (GFP) or phase contrast (PC) microscopy and the magnification used is indicated under each image pair.
Mentions: At 5 d post-blood meal, the L. verrucarum digestive tract continued to be colonized by B. bacilliformis beyond the boundary of the AM (Fig 5). Colonization of L. longipalpis examined at this time point exhibited a significant decrease in density, where minute GFP signals, and questionably viable bacteria, were observed. One example of a questionable signal, however, was observed in the cibarium of L. longipalpis at 7 d post-blood meal (Fig 6). Thus, by 7d post-blood meal, B. bacilliformis was apparently cleared from L. longipalpis, whereas infection of L. verrucarum was quite apparent.

Bottom Line: After 48 h, B. bacilliformis transitioned from bacillus-shape to a non-motile, small coccoid form and appeared to be digested along with the blood meal in both fly species.The capacity of L. longipalpis to transmit viable B. bacilliformis from infected to uninfected meals was analyzed via interrupted feeds.This study provides significant information toward understanding colonization of sand flies by B. bacilliformis and also demonstrates the utility of L. longipalpis as a user-friendly, live-vector model system for studying this severely neglected tropical disease.

View Article: PubMed Central - PubMed

Affiliation: Division of Biological Sciences, University of Montana, Missoula, Montana, United States of America.

ABSTRACT
Bartonella bacilliformis is a pathogenic bacterium transmitted to humans presumably by bites of phlebotomine sand flies, infection with which results in a bi-phasic syndrome termed Carrión's disease. After constructing a low-passage GFP-labeled strain of B. bacilliformis, we artificially infected Lutzomyia verrucarum and L. longipalpis populations, and subsequently monitored colonization of sand flies by fluorescence microscopy. Initially, colonization of the two fly species was indistinguishable, with bacteria exhibiting a high degree of motility, yet still confined to the abdominal midgut. After 48 h, B. bacilliformis transitioned from bacillus-shape to a non-motile, small coccoid form and appeared to be digested along with the blood meal in both fly species. Differences in colonization patterns became evident at 72 h when B. bacilliformis was observed at relatively high density outside the peritrophic membrane in the lumen of the midgut in L. verrucarum, but colonization of L. longipalpis was limited to the blood meal within the intra-peritrophic space of the abdominal midgut, and the majority of bacteria were digested along with the blood meal by day 7. The viability of B. bacilliformis in L. longipalpis was assessed by artificially infecting, homogenizing, and plating for determination of colony-forming units in individual flies over a 13-d time course. Bacteria remained viable at relatively high density for approximately seven days, suggesting that L. longipalpis could potentially serve as a vector. The capacity of L. longipalpis to transmit viable B. bacilliformis from infected to uninfected meals was analyzed via interrupted feeds. No viable bacteria were retrieved from uninfected blood meals in these experiments. This study provides significant information toward understanding colonization of sand flies by B. bacilliformis and also demonstrates the utility of L. longipalpis as a user-friendly, live-vector model system for studying this severely neglected tropical disease.

No MeSH data available.


Related in: MedlinePlus