Experimental infection of Panamanian Phlebotomus sandflies with Leishmania

Hertig, Marshall; McConnell, E.

doi:10.1016/0014-4894(63)90014-6

Cited by 46 publications

(27 citation statements)

References 5 publications

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“…A likely reason why ACL transmission does not occur on domestic environments in endemic areas of Panama is that dogs and humans appear to be dead end-hosts for Le. ( V ) panamensis [4,11,44,49]. …”

Section: Reviewmentioning

confidence: 99%

“…Studies by Rutledge and Ellenwood [49] used soil emergence traps in the forest floor of Gamboa, central Panama, to test for larval-habitat associations in sand flies. Lutzomyia trapidoi was most abundant on open forest floor, whereas Lu.…”

Section: Reviewmentioning

confidence: 99%

“…Studies of vertical stratification of sand flies in Panama were conducted in forest environments using both resting and blood-seeking samples as well as various collecting methods (e.g., human and animal baits, light traps and resting collections) [11,40,49,68,80-83]. In general, the results suggested that there is some degree of vertical partitioning of the niche because females of most species tend to cluster at the ground level, but few of them are active in the canopy.…”

Section: Reviewmentioning

confidence: 99%

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American Cutaneous Leishmaniasis in Panama: a historical review of entomological studies on anthropophilic Lutzomyia sand fly species

Dutari

Loaiza

2014

Parasites & Vectors

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We review existing information on the epidemiology of American Cutaneous Leishmaniasis (ACL) in Panama, with emphasis on the bionomics of anthropophilic Lutzomyia sand fly species. Evidence from Panamanian studies suggests that there are six anthropophilic species in the country: Lutzomyia trapidoi, Lu. panamensis, Lu. gomezi, Lu. ylephiletor, Lu. sanguinaria and Lu. pessoana (Henceforth Lu. carrerai thula). In general, these taxa are abundant, widespread and feed opportunistically on their hosts, which make them potential transmitters of pathogens to a broad range of wildlife, domesticated animals and humans. Furthermore, nearly all man-biting species in Panama (with the exception of Lu. gomezi) expand demographically during the rainy season when transmission is likely higher due to elevated Leishmania infection rates in vector populations. Despite this, data on the distribution and prevalence of ACL suggest little influence of vector density on transmission intensity. Apart from Lu. trapidoi, anthropophilic species seem to be most active in the understory, but vertical stratification, as well as their opportunistic feeding behavior, could vary geographically. This in turn seems related to variation in host species composition and relative abundance across sites that have experienced different degrees of human alteration (e.g., deforestation) in leishmaniasis endemic regions of Panama.

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Section: Reviewmentioning

confidence: 99%

Section: Reviewmentioning

confidence: 99%

Section: Reviewmentioning

confidence: 99%

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American Cutaneous Leishmaniasis in Panama: a historical review of entomological studies on anthropophilic Lutzomyia sand fly species

Dutari

Loaiza

2014

Parasites & Vectors

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“…Forced feeding was performed as described previously (Hertig and Mcconnel, 1963;Anez et al, 1997). Microcapillaries were prepared by constricting the extremities of glass capillary tubes, in an alcohol flame, in order to permit the introduction of the insect mouthparts (except the labium) into the narrowed channel obtained.…”

Section: Forced Feedingmentioning

confidence: 99%

The physiology of the midgut ofLutzomyia longipalpis(Lutz and Neiva 1912): pH in different physiological conditions and mechanisms involved in its control

Santos

Araújo

Machado

et al. 2008

Journal of Experimental Biology

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SUMMARYNutrient digestion and absorption after blood feeding are important events for Lutzomyia longipalpis, which uses these nutrients to produce eggs. In this context, the pH inside the digestive tract is an important physiological feature as it can markedly influence the digestive process as well as interfere with Leishmania development in infected phlebotomines. It was described previously that unfed females have an acidic midgut (pH 6). In this study, the pH inside the midgut of blood-fed females was measured. The abdominal midgut (AM) pH varied from 8.15±0.31 in the first 10 h post-blood meal to 7.7±0.17 after 24 h. While the AM was alkaline during blood digestion, the pH in the thoracic midgut (TM) remained acidic (5.5-6.0). In agreement with these findings, the enzyme α-glucosidase, which has an optimum pH of 5.8, is mainly encountered in the acidic TM. The capacity of unfed females to maintain the acidic intestinal pH was also evaluated. Our results showed the presence of an efficient mechanism that maintains the pH almost constant at about 6 in the midgut, but not in the crop. This mechanism is promptly interrupted in the AM by blood ingestion. RT-PCR results indicated the presence of carbonic anhydrase in the midgut cells, which apparently is required to maintain the pH at 6 in the midgut of unfed females. Investigations on the phenomenon of alkalization observed after blood ingestion indicated that two mechanisms are involved: in addition to the alkalization promoted by CO 2 volatilization there is a minor contribution from a second mechanism not yet characterized. Some inferences concerning Leishmania development and pH in the digestive tube are presented.

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“…Similar flies of the same series were force-fed from glass capillaries (NSRI, Christian Bardram, Denmark) by using the modified technique (17) of Hertig and McConnell (18). The feeding solution contained 5% bovine serum albumin, 0.45% NaCl, and 0.5% (wt/vol) food dye marker (indigotine 73015, Stem, Natania, Israel) in water.…”

Section: Methodsmentioning

confidence: 99%

Leishmania infections damage the feeding mechanism of the sandfly vector and implement parasite transmission by bite.

Schlein¹,

Jacobson²,

Messer³

1992

Proc. Natl. Acad. Sci. U.S.A.

114

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Leishmania parasites are transmitted by the bites of infected female sandflles by a mechanism that has not been clarified. Leishmania infections in the vector develop only in the gut, and the parasites' exit is through the food channel in the proboscis. The problem is how during the bite, when blood flows in, parasites are emitted through the same channel in the opposite direction. It is well documented that infected sandfles maintained on sugar diets are potent vectors, whereas transmission fails after constant feeding on blood. Hence to study the mechanism of transmision, we fed these diets to Phkibotomus papatasi infected with L. maor. Histological examination demonstrated that only in the sugar-fed flies did the cuticle lining of the cardiac valve detach and other valve tissues degenerate gradually. The ijury of the main valve of the food pumps hindered gorging of most flies when force-fed from capillaries, and they regurgitated the gut contents with fluids from the capillaries. We suggest that infections are caused by parasites regurgitated from the stomach that are deposited in the host tissue. We found that secretion of chitinolytic enzymes by cultured L. major parasites is inhibited by blood or hemoglobin, and hence these enzymes are apparently absent from the blood-fed infected flies, where the cardiac valve appears undamaged. We therefore presume that lysis ofthe chitin in the cuticle lining of the valve leads to exposure and degeneration of the underlying tissues.Protozoa parasites of the genus Leishmania (Kinetoplastida: Trypanosomatidae) are causative agents of several diseases that are important public health problems in many countries. The vectors of these parasites are sandflies, and they infect humans and animal reservoirs of the diseases. The developmental cycle ofLeishmania in the sandfly is exclusively in the gut, and parasites reach the host tissue via the food channel in the proboscis. During the bite of infected sandflies the ingested blood is pumped into the gut while at the same time and through the same channel, parasites are deposited in the opposite direction. Evidently, in this system the transmission of the parasites is not implemented by the normal process of ingestion, and additional factors have to be involved. The common opinion was that transmission depends on the presence of parasites in part of the feeding system of the sandfly. The debate was whether parasites facilitate transmission by disturbing the flow of ingested blood or whether they are directly deposited from the proboscis by the act of probing (reviewed in refs. 1-7). These theories were not correlated to transmission experiments, and both the manner and the circumstances of transmission were (8) and still are (9) a major problem in the study of leishmaniasis. We have previously reported that Leishmania major infections in the vector Phlebotomus papatasi cause degeneration of the cardiac valve, the main valve of the feeding system, presum-

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Experimental infection of Panamanian Phlebotomus sandflies with Leishmania

Cited by 46 publications

References 5 publications

American Cutaneous Leishmaniasis in Panama: a historical review of entomological studies on anthropophilic Lutzomyia sand fly species

American Cutaneous Leishmaniasis in Panama: a historical review of entomological studies on anthropophilic Lutzomyia sand fly species

The physiology of the midgut ofLutzomyia longipalpis(Lutz and Neiva 1912): pH in different physiological conditions and mechanisms involved in its control

Leishmania infections damage the feeding mechanism of the sandfly vector and implement parasite transmission by bite.

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