simple micro-assay method for estimating blood meal size of the sand fly, phlebotomus langeroni [diptera: psychodidae]

The accurate measurement of blood meal size in Phlebotomus langeroni, the potential vector of infantile visceral leishmaniasis in Egypt, is important to determine the number of parasites taken in fully engorged insects. A simple protein content micro-assay was introduced for that purpose. The accuracy of this method was confirmed by hemoglobin estimation method. Laboratory bred P. langeroni were fed artificially on defibrinated human blood and the fully engorged flies were carefully dissected on ice, within 1-10 minutes after feeding, since the time of dissection was critical. The serial concentrations of the defibrinated human blood were required as standards. The results showed that the full blood meal taken by P. langeroni ranged from 0.76 to 0.94 mm3 of blood with a mean volume of 0.85 +/- 0.02 mm3 and from 0.71 to 0.99 mm3 of blood with a mean volume of 0.83 +/- 0.02 mm3 as measured by protein content and hemoglobin estimation methods, respectively. Data showed that there was no significant difference between the two methods in estimating the blood meal size of P. langeroni. In addition, protein content micro-assay had the advantages of being accurate, rapid, sensitive and reliable

Vector-host-parasite inter-relationships in leishmaniasis. I. the effect of Leishmania parasites on rate of digestion of blood proteins from various vertebrate hosts by the sand fly phlebotomus langeroni [diptera: psychodidae]

Protein digestion in the gut of Phlebotomus langeroni [Nitzulescu] was studied at 4 subsequent 24-hour intervals post feeding on human, dog [Canis familiaris], rat [Rattus rattus] and turkey [Melagris gallopava] blood with and without Leishmania infantum or L. major promastigotes. Most of the proteins of the studied blood meals were digested within 96 hours. The percentage of blood proteins digested in the first 48 hours was higher than in the second 48 hours in all cases of the studied blood meals, except the normal blood of the turkey, in which the ratio of the digested blood proteins in the 2 periods was 1: 1. During the first 48 hours, the percentage of the digested blood proteins was lower than normal in the presence of L. infantum in case of human and dog blood meals. The reverse was true in case of the rat and turkey blood meals in the presence of L. infantum and in the blood meals from each of the 4 vertebrate hosts in the presence of L. major. The significance of these findings, considering L. infantum as a natural parasite of P. langeroni in El-Agamy focus, was discussed

Vector-host-parasite inter-relationships in leishmaniasis. II-Influence of blood meal from natural vertebrate hosts with and without leishmaniasis infantum and L. major on the proteolytic activity in the gut of phlebotomus langeroni [diptera: Psychodidae]

Proteolytic activity in the gut of Phlebotomus langeroni [Nitzulescu] was studied at 4 subsequent 24-hour intervals post feeding on human, dog [Canis familiaris], rat [Rattus rattus] and turkey [Melagris gallopava] blood with and without Leishmania infantum or L. Major promastigotes. The gut proteolytic activity increased gradually after feeding to reach a maximum at 48 hours post feeding on any of the 12 studied blood meals. In all cases, the activity declined after 48 hours and almost terminated by 96 hours. In case of normal blood, the proteolytic activity, at 48 hours post feeding, was the highest in case of the dog, followed by human, rat and turkey, respectively. Promastigotes were alive and active in fresh gut smears of P. langeroni fed on human, dog and rat blood mixed with either L. infantum or L. major, throughout the digestion period [1 - 4 days]

Vector-host parasite inter-relation in leishmaniasis-III-impact of blood meal from natural vertebrate hosts on the survival and the development of L. infantum and L. major in phlebotomus langeroni [Diptera: Psychodidae]

Phlebotomus langeroni collected from a leishmaniasis endemic focus at El-Agamy, Alexandria, Egypt, were found to fed on blood from man, dogs [Canis familiaris] and rats [Rattus rattus]. The effect of the kind of blood meal on the development and the life cycle of L. infantum and L. major in laboratory reared P. langeroni was investigated. A membrane feeding technique was used to infect sand flies. Gut smears of infected females were examined immediately after feeding and daily for 16 days. Nectomonads and short promastigote forms of L. infantum or L. major were detected in females fed on human, dog and rat blood at all intervals. Paramastigotes [infective stage] were present only in females fed on dog blood containing L. infantum or L. major and in those fed on rat blood containing L. major

Vector-host-parasite inter relationships in leishmaniasis. Iv-electrophoretic studies on proteins of four vertebrate blood with and without Leishmania infantum or L. Major

Fifty-five protein bands with relative mobilities of 8.954 to 245.471 kilo Daltons [kD] were electrophoretically separated from 12 feeding media of blood from 4 natural vertebrate hosts of Phlebotomus langeroni. The feeding media included human, dog [Canis familiaris], rat [Rattus rattus] and turkey [Melagris gallopava] blood with or without Leishmania infantum or L. major promastigotes. Protein bands were identical among the feeding media of one host's blood but varied in number [24 - 28 bands] and relative mobilities among the various hosts' blood. Some protein fractions were common among the various hosts' blood, others were only present in 2 or 3 hosts' blood and some were restricted to one host blood and were unique for each host. This study provided data that may help in understanding that blood from different natural hosts may variably influence the life cycle of Leishmania parasite in the sand fly gut