Detection of tick blood parasites in Egypt using PCR assay I--Babesia bovis and Babesia bigemina.

Babesia bovis and Babesia bigemina are distributed all over the world; the etiologic agents of the animal babesiosis are considered the most important tick-borne disease. The present research work was the first attempt to determine the prevalence of B. bovis and B. bigemina infection in ticks, in Egypt, by using polymerase chain reaction (PCR). Questing 5,243 hard and soft ticks were collected from different localities throughout the Giza Governorate. Furthermore, DNA from 500 different individual tick species was extracted and PCR was performed. Primers verified from the sequence of Mexico strain of both species were used. Two fragments of 275 and 175 bp of B. bovis and B. bigemina, respectively, were generated. Fragments of the pathogens were recovered with PCR and sequenced. The prevalence of B. bovis and B. bigemina in Boophilus annulatus ticks were 55% and 66%, respectively. Also, presence of 12% dual infection with B. bovis and B. bigemina was observed. Sequence analysis of PCR product of these pathogens shares a high degree of similarity in sequence compared to similar species found in GenBank.

Filariasis elimination in Egypt: impact of low microfilaraemics as sources of infection for mosquitoes.

The elimination strategy for lymphatic filariasis aims at reducing blood microfilaraemia to levels at which vector transmission cannot be sustained. We aimed to determine whether patients with pre-treatment low or ultra-low microfilaria (MF) counts could be a reservoir of infection after mass drug administration (MDA) with a combined regimen. Laboratory-reared mosquitoes were fed on 30 volunteers after 2 rounds of MDA. Microfilaria uptake, infectivity rates and number of Wuchereria bancrofti L3 per mosquito were assessed. One year after MDA-1, 6 subjects transmitted MF, but up to 9 months after MDA-2 transmission failed. Six months after MDA-2 > 90% had clear MF smears and either failed to transmit MF or transmitted MF that did not develop to L3. We conclude that the transmission cycle is seriously weakened after MDA-2.

Filariasis elimination in Egypt: impact of low microfilaraemics as sources of infection for mosquitoes

The elimination strategy for lymphatic filariasis aims at reducing blood microfilaraemia to levels at which vector transmission cannot be sustained. We aimed to determine whether patients with pre-treatment low or ultra-low microfilaria [MF] counts could be a reservoir of infection after mass drug administration [MDA] with a combined regimen. Laboratory-reared mosquitoes were fed on 30 volunteers after 2 rounds of MDA. Microfilaria uptake, infectivity rates and number of Wuchereria bancrofti L3 per mosquito were assessed. One year after MDA-1, 6 subjects transmitted MF, but up to 9 months after MDA-2 transmission failed. Six months after MDA-2 > 90% had clear MF smears and either failed to transmit MF or transmitted MF that did not develop to L3. We conclude that the transmission cycle is seriously weakened after MDA-2

Laboratory rearing of Wohlfahrtia nuba Wiedemann (Diptera-Sarcophagidae) in Egypt.

A colony of Wohlfahrtia nuba Wiedemann was set up in the laboratory starting from flies collected from Dier El Anba Shounouda from Sohag City. Procedures for successful establishment of a colony and laboratory maintenance of this fly are described. Duration of the whole larval and pupal stage under insectary and controlled conditions was studied. Effect of controlled temperatures 17, 27 and 32 degrees C on the duration of the three larval instars, the moulting process and mortality rate were also observed.

Experimental transmission and field isolation studies implicating Culex pipiens as a vector of Rift Valley fever virus in Egypt.

Attempts were made to isolate virus from wild caught mosquitoes during the 1977 and 1978 Rift Valley fever (RVF) epizootics in Egypt. Over 95% of the 55,126 mosquitoes collected from epizootic areas in the Nile Delta and Valley were Culex pipiens. Two strains of RVF virus were isolated from unengorged female C. pipiens taken in 1978. Laboratory-reared C. pipiens originating from a population sample from the Nile Delta epizootic area transmitted RVF virus. The infection rate of mosquitoes that fed on viremic hamsters was 86.7%; the transmission rate was 40.0% (46.2% based only on infected mosquitoes). From these results, it is suggested that C. pipiens was a vector of RVF virus during the 1977-1978 epizootics in Egypt.

The Rift Valley fever epizootic in Egypt 1977-78. 2. Ecological and entomological studies.

Epidemiological factors related to the introduction, spread and maintenance of Rift Valley fever (RVF) virus were studied during the 1977-78 epizootic in Egypt, Culex pipiens is the most ubiquitous and prevalent mosquito species in the Nile Valley and Delta. Isolation of RVF virus from unengorged C. pipiens, and demonstration of laboratory transmission of the virus by this species, strongly implicate it as the chief vector in Egypt. Virus transmission to man also occurs by contamination when handling infected meat and by inhaling natural virus aerosols. Wild rodents apparently do not serve as RVF virus reservoirs. Domestic sheep, cattle, buffaloes, camels, goats, donkeys and dogs act as amplifying hosts. Over 30% of the camels sampled at the southern border of Egypt were serologically positive for antibodies to RVF virus and it appears likely that the virus was introduced into Egypt, either by these animals or by other vehicles from the south.