Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 21
Filter
Add more filters










Publication year range
2.
Parasite ; 13(4): 327-9, 2006 Dec.
Article in English | MEDLINE | ID: mdl-17285855

ABSTRACT

Standard WHO insecticide bioassay tests were carried out in Gorgora, northern Ethiopia to evaluate the susceptibility status of Anopheles pharoensis Theobald for the insecticides DDT, malathion, permethrin and deltamethrin. The mortality and when appropriate knockdown effect of the insecticides were observed. The results indicated that this species was resistant to DDT. A high mortality was obtained after exposure to permethrin and deltamethrin but below 97 % which is the limit for susceptibility according to WHO. A prolonged knockdown time was noted for DDT and the two pyrethroids. An. phoaroensis was found to be susceptible to malathion.


Subject(s)
Anopheles/drug effects , DDT/pharmacology , Insecticide Resistance , Insecticides/pharmacology , Mosquito Control/methods , Animals , Biological Assay , Drug Synergism , Ethiopia , Female , Malathion/pharmacology , Nitriles/pharmacology , Permethrin/pharmacology , Pyrethrins/pharmacology
3.
Parassitologia ; 47(1): 135-44, 2005 Mar.
Article in English | MEDLINE | ID: mdl-16044682

ABSTRACT

A risk assessment model was developed for onchocerciasis distribution and its control in Ethiopia using Geographic Information System (GIS) methods. GIS data analysis was done to generate 3 separate risk models using selected environmental features of (1) earth observing satellite data on Normalized Difference Vegetation Index (NDVI) and midday Land Surface Temperature (LST) prepared from AVHRR sensor data of the Global land 1-km project for the years 1992 and 1995, (2) FAO agroclimatic databases from the Crop Production System Zone (CPSZ) of the Intergovernmental Authority on Development (IGAD) sub-region of East Africa, and (3) a climate-based forecast index based on the growing degree days (GDD) and water budget concepts. Parasitological data used for the analysis were published and unpublished reports of onchocerciasis surveillance made between 1969 and 2000 in various parts of the country. Analysis of queries based on 1992 and 1995 annual wet and dry season data of the Global land 1-km project resulted in a predictive value of 95.1%, 94.0% and 96.3%, respectively, using data values extracted from buffers centered on sites above 5% prevalence. The model based on CPSZ data predicted an endemic area that best fit the distribution of sites over 5% prevalence; the query was based on CPSZ values of average altitude (442-2134 m), annual mean temperature (18-28 degrees C), annual rainfall (822-1980 mm), annual potential evapotranspiration (1264-1938 mm), rain minus potential evapotranspiration (-124 - 792 mm), average NDVI x 100 (2000-5000) and average terrain percent slope (9-34). The climate-based model based on GDD and water-budget predicted high risk to severe risk areas in the western and southwestern parts of the country. All three of the models predicted suitable areas for the transmission of onchocerciasis outside known endemic areas, suggesting the need for ground-based validation and potential application to current community-directed treatment programs with ivermectin (CDTI) for control of onchocerciasis in Ethiopia.


Subject(s)
Geographic Information Systems , Models, Theoretical , Onchocerciasis/prevention & control , Satellite Communications , Agriculture , Animals , Anthelmintics/therapeutic use , Climate , Cluster Analysis , Databases, Factual , Endemic Diseases , Ethiopia/epidemiology , Forecasting , Humans , Insect Vectors/parasitology , Ivermectin/therapeutic use , Onchocerciasis/epidemiology , Onchocerciasis/transmission , Prevalence , Risk Assessment , Seasons , Simuliidae/parasitology
4.
Acta Trop ; 90(1): 73-86, 2004 Mar.
Article in English | MEDLINE | ID: mdl-14739026

ABSTRACT

The distribution of two principal vectors of kala-azar in East Africa, Phlebotomus martini and Phlebotomus orientalis were analysed using geographic information system (GIS) based on (1) earth observing satellite sensor data: Normalized Difference Vegetation Index (NDVI) and midday Land Surface Temperature (LST) derived from advanced very high resolution radiometer (AVHRR) of the global land 1km project of United States Geological Survey (USGS), (2) agroclimatic data from the FAO Crop Production System Zone (CPSZ) of the Intergovernmental Authority on Development (IGAD) sub-region, and (3) the FAO 1998 soils digital map for the IGAD sub-region. The aim was to produce a predictive risk model for the two vectors. Data used for the analysis were based on presence and absence of the two species from previous survey collections in the region (mainly Ethiopia, Kenya and Somalia). Annual, wet season and dry season models were constructed. Although all models resulted in more than 85% positive predictive values for both species, the best fit for the distribution of P. martini was the dry season composite (NDVI 0.07-0.38 and LST 22-33 degrees C) with a predictive value of 93.8%, and the best fit for P. orientalis was the wet season composite (NDVI -0.01 to 0.34 and LST 23-34 degrees C) with a predictive value of 96.3%. The two seasonal composites models derived from satellite data were largely similar with best fit models developed based on the CPSZ climate data: average altitude (12-1900m), average annual mean temperature (15-30 degrees C), annual rainfall (274-1212mm), average annual potential evapotranspiration (1264-1938mm) and readily available soil moisture (62-113mm) for P. martini; and average altitude (200-2200m), annual rainfall (180-1050mm), annual mean temperature (16-36 degrees C) and readily available soil moisture (67-108mm) for P. orientalis. Logistic regression analysis indicated LST dry season composite of the satellite data, average altitude, mean annual temperature and readily available soil moisture of the CPSZ data as the best ecological determinants for P. martini while LST annual composite was the only important ecological determinant for P. orientalis. Spearman's rank correlation revealed several factors to be important determinants for the distribution of the two vectors. None of the soil types analysed appeared to be important determinant for the two species in East Africa, unlike in Sudan where P. orientalis is mainly associated with eutric vertisol (black cotton clay soil).


Subject(s)
Phlebotomus , Africa, Eastern , Animals , Databases, Factual , Disease Vectors , Ecology , Logistic Models , Seasons
5.
Trans R Soc Trop Med Hyg ; 98(1): 64-70, 2004 Jan.
Article in English | MEDLINE | ID: mdl-14702839

ABSTRACT

In a survey of Leishmania infections in phlebotomine sandflies in a highly suspected focus of leishmaniasis in the Awash Valley (northeastern Ethiopia) between January 1994 and August 1997, a total of 3307 females of 11 Phlebotomus species (P. orientalis, P. fantalensis, P. saevus, P. sergenti, P. gemetchi, P. alexandri, P. bergeroti, P. duboscqi, P. arabicus, P. martini, and P. rodhaini) were dissected. Promastigotes were detected in 17 females of three species (11 P. saevus, 4 P. sergenti and 2 P. arabicus). Of these, only two P. saevus (one from Upper Awash and one from Middle Awash) and three P. sergenti (from Upper Awash) positives were successfully isolated in culture and were typed by isoenzyme analysis. Four isolates (two each from P. saevus and P. sergenti) were identified as new zymodemes (Z) of L. tropica and one isolate from P. sergenti was typed as a new zymodeme of L. aethiopica. This is the first finding of natural infections of P. saevus and P. arabicus and the first evidence for the former to be a vector of L. tropica. This is also the first time P. sergenti has been implicated in L. tropica transmission in Ethiopia; the isolation of L. aethiopica from a Paraphlebotomus species (P. sergenti) is also a new record. The possible presence of human cutaneous leishmaniasis (L. tropica and L. aethiopica), and wild reservoir host(s) of the parasites, especially rock hyrax (Procavia capensis) in the Upper and Middle Awash Valley remain to be determined.


Subject(s)
Leishmania/isolation & purification , Phlebotomus/parasitology , Animals , Ethiopia , Female , Leishmania tropica/isolation & purification
6.
J Hered ; 94(6): 457-63, 2003.
Article in English | MEDLINE | ID: mdl-14691312

ABSTRACT

This study examined the population genetic structure of the major malaria vector, Anopheles arabiensis mosquitoes, in Ethiopia and Eritrea. Ethiopia and Eritrea have great geographical diversity, with high mountains, rugged plateaus, deep gorges, and rolling plains. The plateau is bisected diagonally by the Great Rift Valley into the Northwestern Highlands and the Southeastern Highlands. Five A. arabiensis populations from the Northwestern Highlands region and two populations from high-altitude sites in the Great Rift Valley were genotyped using six microsatellite markers to estimate the genetic diversity and population genetic structure of A. arabiensis. We found that A. arabiensis populations from the Northwestern Highlands and the Great Rift Valley region showed a similar level of genetic diversity. The genetic differentiation (F(ST)) of the five mosquito populations within the Northwestern Highlands region was 0.038 (P <.001), while the two populations within the Great Rift Valley showed little genetic differentiation (F(ST) = 0.007, P <.01). The degree of genetic differentiation between the Northwestern Highlands region and the Great Rift Valley region was small but statistically significant (F(ST) = 0.017, P <.001). The population genetic structure of A. arabiensis in the study area did not follow the isolation-by-distance model (r(2) = 0.014, P >.05). The low F(ST) estimates for A. arabiensis populations in Ethiopia and Eritrea are consistent with the general population genetic structure of this species in East Africa based on other molecular markers.


Subject(s)
Anopheles/genetics , Animals , Eritrea , Ethiopia , Genes, Insect , Genetic Variation , Genetics, Population , Genotype , Linkage Disequilibrium , Microsatellite Repeats
7.
Parassitologia ; 45(1): 1-3, 2003 Mar.
Article in English | MEDLINE | ID: mdl-15270536

ABSTRACT

Anopheles arabiensis strains reared from larvae and pupae collected from two different localities, Metehara and Melka-Worer, eastern Ethiopia, were evaluated against three insecticides. Resistance states of adult females were determined using the WHO test kits under field condition. The insecticides used were WHO discriminating doses of 4% DDT, 0.75% permethrin and 0.1% propoxur. The study revealed that 42.5% of the An. arabiensis population was resistant to DDT in Melka-Worer while only 30% of the species was resistant in Metehara to the same insecticide. In Metehara, 25% of An. arabiensis was also resistant to permethrin while the population was highly susceptible to the insecticide in Melka-Worer. Propoxur, which was not evaluated in Melka-Worer, was highly toxic to An. arabiensis in Metehara. The knocked-down time (KD50) for permethrin was 14.5 and 12.5 minutes in Metehara and Melka-Worer, respectively. The implications of these findings are discussed.


Subject(s)
Anopheles/drug effects , DDT/pharmacology , Insecticides/pharmacology , Permethrin/pharmacology , Propoxur/pharmacology , Animals , Ethiopia , Female , Insect Vectors/drug effects , Insecticide Resistance , Lethal Dose 50 , Mosquito Control , Paper
9.
East Afr Med J ; 79(4): 198-201, 2002 Apr.
Article in English | MEDLINE | ID: mdl-12625676

ABSTRACT

OBJECTIVES: To record the effect of Endod soap and spraying of soaked Endod suspension on the prevalence of human schistosomiasis. DESIGN: A cross-sectional epidemiological study in which pre- and post-intervention parasitological results were compared. SETTING: Kemise, Bati and Harbu towns in northeastern Ethiopia. SUBJECTS: The study subjects included all members of the five per cent households systematically selected from the three towns. RESULTS: In Kemise town, where suspension of ground Endod was sprayed on the stream containing infected snails, the prevalence of the disease was reduced from 59% to 53% and the mean intensity of infection was reduced from 239 eggs per gram (EPG) of faeces to 99 EPG (p < 0.05). In Bati town where Endod soap approach was used, the respective reduction in the prevalence and intensity of infection was from 51% to 43% and from 195 EPG to 162 EPG (p < 0.05). There was also a significant reduction of the disease in the control town probably due to the effects of praziquantel treatment and other factors. CONCLUSION: The reduction achieved in the prevalence and intensity of schistosomiasis after an intervention period of four years was limited. This observation corroborates the fact that molluscicides must always be considered as supplementary to chemotherapy in the control of schistosomiasis. Although both approaches can be used, the spraying approach appears to be simpler and more feasible because two or three times yearly application of Endod suspension would suppress snail population and reduce transmission. Nevertheless, the choice as to what approach to use must be made on the basis of community preference, and for some soap-effect of Endod would be attractive


Subject(s)
Disease Vectors , Fresh Water/parasitology , Medicine, African Traditional , Molluscacides , Pest Control/methods , Phytolacca dodecandra , Schistosomiasis mansoni/epidemiology , Schistosomiasis mansoni/prevention & control , Snails/parasitology , Adolescent , Adult , Age Distribution , Animals , Child , Cross-Sectional Studies , Ethiopia , Feasibility Studies , Female , Humans , Laundering , Male , Pest Control/standards , Population Surveillance , Prevalence , Schistosomiasis mansoni/parasitology , Schistosomiasis mansoni/transmission , Sex Distribution , Soaps , Suspensions
10.
East Afr Med J ; 79(9): 485-90, 2002 Sep.
Article in English | MEDLINE | ID: mdl-12625690

ABSTRACT

OBJECTIVE: To assess the impact of livestock keeping on the human biting rate (HBR) of anopheline mosquitoes and malaria transmission around Ziway in the middle course of the Ethiopian Rift Valley. DESIGN: As a passive experiment, man landing captures were done in homesteads with mixed dwelling, separate cattle shed and without livestock; and as an active experiment, captures were in experimental tukuls (huts) of cattle, goats, and without livestock. Parasite and spleen rates of children were compared among those residents under variable living conditions mentioned for passive experiment. SUBJECTS: For entomological study, human-baits were used for man-landing captures of mosquitoes. Study subjects for parasitological and clinical studies were children below 10 years old. MAIN OUTCOME MEASURES: Human-biting rate (HBR) of anopheline mosquitoes; and the parasite and spleen rates of the study subjects in different living conditions. RESULTS: In the passive experiment, the mean HBR of Anopheles arabiensis in mixed dwelling, separate cattle shed and without livestock was 8.45, 4.64 and 5.97, respectively. Similarly, the HBR of An. pharoensis was 2.88, 1.79 and 1.61, respectively. In the active experiment, the mean HBR of An. arabiensis in tukuls with cattle, goats, and without livestock was 3.50, 3.38 and 1.43 respectively; while that of An. pharoensis was 0.37, 0.70 and 0.55 respectively. Parasitologically, mean parasite rates of 26.67%, 15.05% and 23.85% were, respectively, recorded from children living under the above conditions stated for passive experiment. Similarly, the mean spleen rates of 50.0%, 26.9%, and 47.37% were recorded, respectively. CONCLUSION: These observations in the present study indicate that the presence of cattle in homesteads tends to increase the man biting rate of An. arabiensis, although differences in the mean HBR of vector mosquitoes were not statistically significant for all groups. In contrast, cattle keeping in separate cattle sheds outside of the human dwellings tends to reduce the man biting rate of An. arabiensis and malaria transmission in the study area.


Subject(s)
Animal Husbandry/statistics & numerical data , Animals, Domestic , Anopheles/parasitology , Cattle , Insect Bites and Stings/complications , Insect Bites and Stings/epidemiology , Insect Vectors/parasitology , Malaria, Falciparum/parasitology , Malaria, Falciparum/transmission , Malaria, Vivax/parasitology , Malaria, Vivax/transmission , Adult , Animals , Anopheles/physiology , Child , Endemic Diseases/statistics & numerical data , Ethiopia/epidemiology , Feeding Behavior , Goats , Housing/statistics & numerical data , Housing, Animal/statistics & numerical data , Humans , Insect Vectors/physiology , Malaria, Falciparum/epidemiology , Malaria, Vivax/epidemiology , Seasons , Splenomegaly/epidemiology , Splenomegaly/parasitology , Suburban Health/statistics & numerical data
11.
Parasitol Int ; 50(4): 259-66, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11719112

ABSTRACT

Epidemiological studies were conducted in the Lake Langano area in the Rift Valley of Ethiopia to determine the occurrence of schistosomiasis and assess factors involved in its transmission. Microscopic examination of faecal specimens from free ranging Papio anubis (anubis baboon) troops from Bishan Gari and Burka Dita forest reserves revealed Schistosoma mansoni eggs with a prevalence of 12.1% (11/91) and 26.2%(34/130), respectively. The eggs were viable as confirmed by miracidial hatching and infectivity tests. Out of the total 12 communities (three schools, five villages and one herdsmen community) surveyed for schistosomiasis around Lake Langano, individuals excreting S. mansoni eggs were found in nine communities with prevalence of infection ranging from 1.4 to 43%. The intensity of infection ranged from 24 EPG (eggs per gram of faeces) to 243 EPG. Excretion of viable eggs by the baboons indicate that they play a role in maintenance of S. mansoni infection in the locality. The detection of S. mansoni eggs in young children, collection of cercarial-infected Biomphalaria pfeifferi in water bodies, and establishment of S. mansoni infection in lab-bred mice have confirmed establishment of transmission foci in Kime area, south-east of Lake Langano. However, the lake itself does not seem to support transmission of schistosomiasis since no snails were found along the shore of the Lake. Further investigations are indicated to fully elucidate the role baboons play in the epidemiology of schistosomiasis in the Rift Valley of Ethiopia. The risk of introduction of water-based development projects in these new endemic foci in relation to S. mansoni infection in the baboons is discussed.


Subject(s)
Papio/parasitology , Schistosoma mansoni/isolation & purification , Schistosomiasis mansoni/transmission , Adolescent , Adult , Animals , Biological Assay , Child , Child, Preschool , Ethiopia/epidemiology , Feces/parasitology , Female , Fresh Water , Humans , Infant , Male , Mice , Mice, Inbred BALB C , Middle Aged , Parasite Egg Count , Prevalence , Schistosoma mansoni/growth & development , Schistosomiasis mansoni/epidemiology , Snails/parasitology
12.
East Afr Med J ; 77(2): 116-20, 2000 Feb.
Article in English | MEDLINE | ID: mdl-10774086

ABSTRACT

OBJECTIVE: To determine the prevalence of onchocerciasis and the entomological transmission indices such as the parous rate and annual transmission potential (ATP). SETTING: Gilgel Ghibe village, Gilgel Ghibe River Valley Southwest Ethiopia between April 1994 and March 1995. SUBJECTS: Two hundred twenty eight subjects of the total 400 population in Gilgel Ghibe village were subjected to parasitological and clinical examinations. METHOD: Two skin snips per person were taken and examined for microfilariae of Onchocerca volvulus. Fly collections were done from dawn to dusk from human baits seated in pairs at four representative sites at the river bank and away from the river bank. Flies were dissected for parity and infections with O. volvulus larvae. RESULTS: Among the 228 people examined, the prevalence of the disease was low (17%), being higher in males (19%) than in females (14%). The geometric mean of microfilarial density was 11.1 (range, 1-132) mf per skin snip. Itching followed by pigmentary changes were the most common clinical signs and symptoms. The predominant anthropophilic blackfly species was Simulium (Edwardsellum) damnosum s.l. The annual parous rate and ATP were 74.7% and 1669.5, respectively, being higher at the river bank than at sites further away suggesting a greater risk of infection by the river side. CONCLUSION: The low prevalence of onchocerciasis in Gilgel Ghibe area vis-a-vis the high ATP level could be due to the possible presence of bovine onchocerciasis in the area. Further studies employing molecular techniques are thus required to identify O. volvulus from other filariae in flies.


PIP: 400 people in Gilgel Ghibe, southwestern Ethiopia, were subjected to parasitological and clinical examination to determine the prevalence and intensity of onchocerciasis. Its association with entomological transmission indices such as the parous rate and annual transmission potential (ATP) were determined simultaneously. Two skin snips per person were taken and examined for microfilariae of Onchocerca volvulus. In addition, collections of adult blackfly were done from human baits seated in pairs at 4 representative sites at the riverbank and away from the riverbank. Flies were then dissected for parity and infections with O. volvulus. Among the 228 people examined, the prevalence of the disease was low (17%), being higher in males than in females (19% vs. 14%). The geometric mean of microfilarial density was 11.1 mf per skin snip. Itching and skin changes were the most common signs and symptoms of the disease. The predominant anthropophilic blackfly species was Simulium (Edwardsellum) damnosum s.l. The annual parous rate was 74.7%, while ATP was 1669.5, being higher at the riverbank than at farther sites, suggesting a greater risk of infection by the riverside. In conclusion, the low prevalence of onchocerciasis vis-a-vis the high ATP level could be caused by the possible presence of bovine onchocerciasis in the area. Further studies employing molecular techniques are needed to identify O. volvulus from other filariae in flies.


Subject(s)
Endemic Diseases/statistics & numerical data , Fresh Water/parasitology , Onchocerciasis/epidemiology , Adolescent , Adult , Age Distribution , Animals , Child , Child, Preschool , Ethiopia/epidemiology , Female , Humans , Infant , Male , Mass Screening , Middle Aged , Onchocerciasis/parasitology , Onchocerciasis/transmission , Population Surveillance , Prevalence , Risk Factors , Sex Distribution , Simuliidae/parasitology , Simuliidae/physiology
13.
AIDS ; 13(14): 1921-5, 1999 Oct 01.
Article in English | MEDLINE | ID: mdl-10513651

ABSTRACT

OBJECTIVE: To investigate whether clearance of Leishmania parasites from tissue aspirate smears in patients with HIV and visceral leishmaniasis (VL) co-infection treated with pentavalent antimonials is influenced by initial HIV viral load and to assess the effect of active VL on HIV viral load and replication in vivo. METHODS: Leishmania parasites were identified in Giemsa-stained smears prepared from tissue aspirates. Parasite index was determined by quantifying Leishmania donovani bodies in smears. HIV-1 RNA was quantitated by using the nucleic acid sequence-based amplification technique with a limit of detection of 500 copies/ml. All patients were treated with pentavalent antimonials at 20 mg pentavalent antimony (Sb(V))/kg daily for a total of 28 days. None of the patients received specific anti-retroviral therapy. RESULTS: Seventeen patients (73.9%) showed good initial response to anti-leishmanial treatment and the remaining six (26.1%) had very poor response. Among the good responders, 11 (64.7%) had no demonstrable Leishmania donovani bodies in post-therapy tissue aspirate smear preparations, and in the remaining six (35.3%) their parasite loads were reduced to very low levels. Patients with poor response had persistently high parasite index despite completion of anti-leishmanial chemotherapy. Poor responders had pre-treatment median HIV viral load that was >160-fold higher than responders to anti-leishmanial chemotherapy; [410000 copies/ml (quartile range, 33000-530000) and 2500 copies/ml (quartile range 500-297500), respectively]. Furthermore, compared with pre-treatment viral concentrations, patients with good response showed marked reduction in post-treatment viral load. In contrast, post-treatment HIV viral concentrations were markedly increased among patients with poor response to anti-leishmanial therapy. CONCLUSIONS: The results suggest that pre-treatment HIV viral load influences response to anti-leishmanial chemotherapy and active VL is associated with increased viral replication in vivo, supporting the notion that dual infection plays an important role in the pathogenesis and disease progression of either infection.


Subject(s)
AIDS-Related Opportunistic Infections/drug therapy , AIDS-Related Opportunistic Infections/virology , Antimony/therapeutic use , Antiprotozoal Agents/therapeutic use , HIV-1 , Leishmania donovani , Leishmaniasis, Visceral/drug therapy , Leishmaniasis, Visceral/virology , Viral Load , AIDS-Related Opportunistic Infections/parasitology , Adult , Animals , Female , HIV-1/genetics , Humans , Leishmaniasis, Visceral/parasitology , Male , Middle Aged , Treatment Outcome
14.
Ethiop Med J ; 36(2): 113-22, 1998 Apr.
Article in English | MEDLINE | ID: mdl-10214453

ABSTRACT

A clinico-epidemiological study of cutaneous leishmaniasis (CL) and visceral leishmaniasis (VL) was undertaken involving 1,809 residents of ten representative villages from Zeway-Langano, Wajifo-Mirab-Abaya and Blate-Dimtu areas in the middle course of the Ethiopian Rift Valley from November 1994 to June 1996. Community prevalence of positive leishmanin skin test (LST) was very low ranging from 5% in Olge village to 0% in Kello-Langano area. Sera collected from 57 clinical VL suspects originating from the different villages tested negative for anti-leishmanial antibodies. The rate of splenomegaly ranged from 5% in Kello-Langano area to as high as 80% in Korga village. Furthermore, the frequency and size of splenomegaly was related to the reported past and recent history of attack(s) of malaria. The low community prevalence of LST suggests minimal transmission of leishmania infections in spite of the knowledge of the presence of the sandfly vectors of CL and VL in the area. However, with increasing villagization and agricultural development activities, the potential risk for the establishment of VL and/or CL as endemic diseases can not be excluded.


Subject(s)
Antigens, Protozoan , Leishmaniasis/diagnosis , Leishmaniasis/epidemiology , Skin Tests/methods , Adolescent , Adult , Age Distribution , Child , Child, Preschool , Endemic Diseases/statistics & numerical data , Ethiopia/epidemiology , Female , Health Surveys , Humans , Infant , Leishmaniasis/immunology , Leishmaniasis/parasitology , Male , Middle Aged , Population Surveillance , Prevalence , Seroepidemiologic Studies , Sex Distribution
15.
J Med Entomol ; 34(4): 383-6, 1997 Jul.
Article in English | MEDLINE | ID: mdl-9220670

ABSTRACT

Morphometric evaluation of 27 characters of allopatric females of the closely related species, Phlebotomus duboscqi Neveu-Lemaire and P. bergeroti Parrot, was made in Ethiopia with the aim of finding reliable means to distinguish sympatric specimens. By applying stepwise discriminant analysis, 100% correct classification was obtained using 8 characters. However, 2 of these characters, C3 and C4 (respective distances from sockets of the longest ascoids on segment 3 and 4 to distal margin of the segment) with the highest discriminant loadings, separated these 2 species with a success rate of 98%. It is recommended that these 2 characters be used in the routine identification of these species.


Subject(s)
Phlebotomus/anatomy & histology , Phlebotomus/classification , Animals , Ethiopia , Female , Multivariate Analysis , Sex Characteristics , Species Specificity
16.
Ann Trop Med Parasitol ; 90(5): 523-31, 1996 Oct.
Article in English | MEDLINE | ID: mdl-8915129

ABSTRACT

The sandfly subgenus Phlebotomus (Larroussius) contains species which transmit parasites causing cutaneous and visceral leishmaniasis in East Africa, including Ethiopia. The Gewasha caves in central Ethiopia harbour a new species (Phlebotomus ashfordi) belonging to the subgenus Larroussius and previously identified as P. (L.) aculeatus Lewis, Minter and Ashford. Although generally similar to P. (L.) aculeatus and P. (L.) elgonensis Ngoka, Madel and Mutinga, the species is distinct in eight male characters and in the female spermatheca. Given its taxonomic affinity to known vectors of cutaneous leishmaniasis and the presence of disease in the Gewasha caves area, the medical importance of this species needs to be assessed.


Subject(s)
Phlebotomus/classification , Animals , Biometry , Ethiopia , Female , Male , Phlebotomus/anatomy & histology
17.
Med Vet Entomol ; 10(1): 44-52, 1996 Jan.
Article in English | MEDLINE | ID: mdl-8834742

ABSTRACT

From May 1984 to May 1985, the transmission of onchocerciasis by blackflies (Dipteria: Simuliidae) was studied around Gilgel Ghibe and Gojeb rivers in southwest Ethiopia. The predominant anthropophilic species of Simulium at both localities were S. (Edwardsellum) damnosum sensu lato and S. (Lewisellum) ethiopiense. Some S. (Anasolen) dentulosum also landed on human bait at Gilgel Ghibe river. Dissections of S. damnosum from Gilgel Ghibe and Gojeb revealed mean parous rates of 92% (n = 18,291) and 84% (n = 9530), respectively. S. ethiopiense from Gilgel Ghibe and Gojeb showed mean parous rates of 53% (n = 322) and 93% (n = 14), respectively. Of the parous S. damnosum, 1.3% at Gilgel Ghibe and 0.5% at Gojeb harboured infective third-stage larvae (L3) of Onchocerca volvulus (or morphologically indistinguishable from it). Unknown filariae of animal origin, indicative of zoophily, were found in 0.3% and 0.7% of Simulium damnosum complex females from Gilgel Ghibe and Gojeb, respectively. S. ethiopiense harboured developing (L1) larvae only, with 7.7% infection rate in both localities. In contrast, S. dentulosum did not harbour any filaria larvae. The annual infective biting rate (AIBR) and transmission potential (ATP) of the S. damnosum complex at Gilgel Ghibe river were 858 and 5478, respectively. The AIBR and ATP of S. damnosum s.l. at Gojeb river were 519.5 and 1963, respectively. These results emphasize the predominant role of the S. damnosum complex in the transmission of O. volvulus in southwest Ethiopia.


Subject(s)
Onchocerca volvulus , Simuliidae/parasitology , Animals , Ethiopia , Female , Insect Bites and Stings , Onchocerciasis/parasitology , Onchocerciasis/transmission , Population Density , Seasons , Simuliidae/classification
18.
Med Vet Entomol ; 10(1): 53-62, 1996 Jan.
Article in English | MEDLINE | ID: mdl-8834743

ABSTRACT

During field studies (December 1988 to April 1990) to determine the vectors of visceral leishmaniasis (kala-azar) in the Aba Roba (Segen Valley) focus of southern Ethiopia, a total of 40,770 sandflies (Diptera: Psychodidae: Phlebotominae) were collected and identified as six species of Phlebotomus and seventeen Sergentomyia spp. Nine of these species were anthropophilic (four Phlebotomus and five Sergentomyia spp.), the dominant being Phlebotomus (Synphlebotomus) martini, P.(S.)celiae and Sergentomyia (Sergentomyia) schwetzi. P.celiae adult populations increased during the rainy season. Of 2326 P.martini and 1044 P.celiae dissected, the parous rate was 29.9% and 24.4%, respectively. Leishmania promastigotes were detected in sixteen P.martini (eleven identified as L.donovani by isoenzyme analysis and/or a DNA probe) and in three P.celiae (two identified by DNA probe), giving overall infection rates of 0.7% (1.9% parous infection rate) and 0.3% (1.2% parous infection rate), respectively. Four isolates from P.martini were typed by their isoenzyme profile as L.donovani zymodeme MON-37 = LON-44, identical to one of the zymodemes isolated from patients in this focus. This is the first evidence that P.celiae is a vector and the first time that P.martini has been implicated in Ethiopia. Based on observations of abundance, seasonality and prevalence of infection of the two Synphlebotomus spp., it is concluded that P.martini is the major vector and P.celiae a secondary vector in the Aba Roba focus. The risk of infection with L.donovani is greatest during the wet season.


Subject(s)
Insect Vectors/parasitology , Leishmania donovani/isolation & purification , Phlebotomus/parasitology , Animals , Ethiopia , Female , Humans , Insect Bites and Stings , Insect Vectors/classification , Leishmaniasis, Visceral/parasitology , Phlebotomus/classification , Seasons
20.
Trans R Soc Trop Med Hyg ; 87(1): 10-1, 1993.
Article in English | MEDLINE | ID: mdl-8465376

ABSTRACT

In a survey of Leishmania infections in phlebotomine sandflies in visceral leishmaniasis focus at Aba Roba, Segen Valley, southern Ethiopia, Phlebotomus duboscqi was found naturally infected with L. major (zymodeme MON-74). This is the first isolation of L. major from a vector sandfly in Ethiopia, from an area where human and/or rodent infections with L. major are, so far, unknown.


Subject(s)
Insect Vectors , Leishmania tropica/isolation & purification , Phlebotomus/parasitology , Animals , Ethiopia
SELECTION OF CITATIONS
SEARCH DETAIL
...