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Alwajeeh TS, Abdul-Ghani R, Allam AF, Farag HF, Khalil SSM, Shehab AY, El-Sayad MH, Alharbi RA, Almalki SSR, Azazy AA. Uncomplicated falciparum malaria among schoolchildren in Bajil district of Hodeidah governorate, west of Yemen: association with anaemia and underweight. Malar J 2020; 19:358. [PMID: 33028361 PMCID: PMC7542704 DOI: 10.1186/s12936-020-03431-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 10/01/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria, malnutrition and anaemia are major public health problems in Yemen, with Hodeidah being the most malaria-afflicted governorate. To address the lack of relevant studies, this study was conducted to determine the prevalence of Plasmodium falciparum and its relation to nutritional status and haematological indices among schoolchildren in Bajil district of Hodeidah governorate, west of Yemen. METHODS A cross-sectional study was conducted among 400 schoolchildren selected randomly from four schools in Bajil district. Data about demographic characteristics, risk factors and anthropometric measurements of age, height and weight were collected. Duplicate thick and thin blood films were prepared, stained with Giemsa and examined microscopically for malaria parasites. The density of P. falciparum asexual stages was estimated on thick films. EDTA-blood samples were examined for the haematological indices of haemoglobin (Hb) and blood cell counts. RESULTS Plasmodium falciparum was prevalent among 8.0% (32/400) of schoolchildren with a mean parasite density of 244.3 ± 299.3/µL of blood and most infections showing low-level parasitaemia, whereas Plasmodium vivax was detected in one child (0.25%). Residing near water collections was a significant independent predictor of falciparum malaria [adjusted odds ratio (AOR) = 2.6, 95.0% CI 1.20-5.72; p = 0.016] in schoolchildren. Mild anaemia was prevalent among more than half of P. falciparum-infected schoolchildren and significantly associated with falciparum malaria (AOR = 5.8, 95.0% CI 2.39-14.17; p < 0.001), with a mean Hb concentration of 10.7 ± 1.0 g/dL. Although the mean values of the total white blood cells, monocytes and platelets were significantly lower in infected than non-infected schoolchildren, they were within normal ranges. More than half of the children were malnourished, with stunting (39.3%) and underweight (36.0%) being the most prevalent forms of malnutrition; 6.3% of children were wasted. Underweight (AOR = 5.3, 95.0% CI 2.09-13.62; p < 0.001) but not stunting or wasting, was a significant predictor of falciparum malaria among schoolchildren. CONCLUSION Asymptomatic falciparum malaria is prevalent among schoolchildren in Bajil district of Hodeidah Governorate, with predominance of low parasitaemic infections and significant association with mild anaemia and underweight. Residence near water collection is a significant predictor of infection with falciparum malaria among schoolchildren. Further studies among children with severe malaria and those with high parasite densities are recommended.
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Affiliation(s)
- Talal S Alwajeeh
- Laboratory Department, Kuwait University Hospital, Sana'a University, Sana'a, Yemen
| | - Rashad Abdul-Ghani
- Department of Medical Parasitology, Faculty of Medicine and Health Sciences, Sana'a University, Sana'a, Yemen. .,Tropical Disease Research Center, Faculty of Medicine and Health Sciences, University of Science and Technology, Sana'a, Yemen.
| | - Amal F Allam
- Department of Parasitology, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Hoda F Farag
- Department of Parasitology, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Safia S M Khalil
- Department of Parasitology, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Amel Y Shehab
- Department of Parasitology, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Mona H El-Sayad
- Department of Parasitology, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Raed A Alharbi
- Laboratory Medicine Department, Faculty of Applied Medical Sciences, Al Baha University, Al Baha, Saudi Arabia
| | - Shaia S R Almalki
- Laboratory Medicine Department, Faculty of Applied Medical Sciences, Al Baha University, Al Baha, Saudi Arabia
| | - Ahmed A Azazy
- Laboratory Medicine Department, Faculty of Applied Medical Sciences, Al Baha University, Al Baha, Saudi Arabia
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Alharbi RA, Alwajeeh TS, Assabri AM, Almalki SSR, Alruwetei A, Azazy AA. Intestinal parasitoses and schistosome infections among students with special reference to praziquantel efficacy in patients with schistosomosis in Hajjah governorate, Yemen. Ann Parasitol 2019; 65:217-223. [PMID: 31578845 DOI: 10.17420/ap6503.203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The majority of the population in Yemen lives in rural areas and suffers from parasitic infections. Therefore, the present study aimed to determine the prevalence of intestinal parasitoses and schistosome infections among the students enrolled in the primary schools in Hajjah governorate – north of Yemen, along with an assessment of praziquantel (PZQ) in the treatment of microscopy-confirmed cases of Schistosoma mansoni and Schistosoma haematobium. For this purpose, 780 samples (320 stool and 460 urine) were examined microscopically. The present study revealed an overall infection rate of 75.3% (241/320) with intestinal parasites and Schistosoma mansoni. The detected parasite species included Entamoeba histolytica (27.8%), Hymenolepis nana (12.2%), Giardia lamblia (9.7%), Entamoeba coli (9.4%), S. mansoni (9.1%), Ascaris lumbricoides (6.9%), Trichuris trichiura (3.1%), Enterobius vermicularis (2.8%) and Ancylostoma duodenale (2.2%). Schistosoma haematobium was prevalent among 1.7% (8/460) of the investigated students. On the other hand, PZQ yielded a cure rate of 75.7% of Schistosoma-infected students when administered at 40 mg/kg body weight. However, a 100% cure rate was achieved when administered at 60 mg/kg body weight. Therefore, the findings of the present study highlight the importance of monitoring PZQ efficacy through large-scale studies in different settings endemic for schistosomosis in the country.
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Affiliation(s)
- Raed A Alharbi
- Department of Laboratory Medicine, Faculty of Applied Medical Sciences, Al Baha University, Al Baha, Saudi Arabia
| | - Talal S Alwajeeh
- Laboratory Unit, Kuwait University Hospital, Sana’a University, Sana’a, Yemen
| | - Ali M Assabri
- Department of Community Medicine, Faculty of Medicine and Health Sciences, Sana’a University, Sana’a, Yemen
| | - Shaia SR Almalki
- Department of Laboratory Medicine, Faculty of Applied Medical Sciences, Al Baha University, Al Baha, Saudi Arabia
| | - Abdulmohsen Alruwetei
- Department of Medical Laboratory, College of Applied Medical Sciences, Qassim University, Qassim, Saudi Arabia
| | - Ahmed A Azazy
- Department of Laboratory Medicine, Faculty of Applied Medical Sciences, Al Baha University, Al Baha, Saudi Arabia
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Mahdy MAK, Abdul-Ghani R, Abdulrahman TAA, Al-Eryani SMA, Al-Mekhlafi AM, Alhaidari SAA, Azazy AA. Onchocerca volvulus infection in Tihama region - west of Yemen: Continuing transmission in ivermectin-targeted endemic foci and unveiled endemicity in districts with previously unknown status. PLoS Negl Trop Dis 2018; 12:e0006329. [PMID: 29505580 PMCID: PMC5854432 DOI: 10.1371/journal.pntd.0006329] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 03/15/2018] [Accepted: 02/20/2018] [Indexed: 11/29/2022] Open
Abstract
Background Onchocerciasis in Yemen is one of the most neglected diseases, where baseline estimates of onchocerciasis and monitoring of the impact of ivermectin regularly administered to the affected individuals on its transmission are lacking. Therefore, this study aimed to determine the anti-Ov16 IgG4 seroprevalence among local communities of Hodeidah and Al-Mahwit governorates of Tihama region. The factors possibly associated with previous exposure to infection were also studied. Methodology/Principal findings This cross-sectional study was conducted in two ivermectin-targeted districts endemic for onchocerciasis in Hodeidah and Al-Mahwit and two untargeted districts with unknown previous endemicity in Hodeidah between February and July 2017. For 508 residents sampled by a multi-stage random approach, data were collected and blood specimens were screened for anti-Ov16 IgG4 using the SD BIOLINE Onchocerciasis IgG4 rapid tests. The study revealed an overall anti-Ov16 IgG4 rate of 18.5% (94/508) in all surveyed districts, with 10.2% (12/118) of children aged ≤10 years being seropositive. Moreover, rates of 8.0% (4/50) and 6.1% (4/66) were found in districts not officially listed as endemic for the disease. Multivariable analysis confirmed the age of more than ten years and residing within a large family as the independent predictors of exposure to infection. Conclusions/Significance Onchocerciasis transmission is still ongoing as supported by the higher anti-Ov16 IgG4 seroprevalence rate among children aged ≤10 years compared to that (<0.1%) previously set by the World Health Organization as a serologic criterion for transmission interruption. Further large-scale studies combining serologic and entomologic criteria are recommended for the mapping of O. volvulus in human and blackfly populations in endemic foci and their neighboring areas of uncertain endemicity. In addition, ivermectin distribution, coverage and impact on disease transmission need to be continually assessed. Onchocerciasis is endemic in certain foci in the western governorates of Yemen. Monitoring the impact of the regular ivermectin administration to affected individuals on the transmission status and providing baseline onchocerciasis estimates in endemic areas are crucial for planning effective elimination strategies. We found that the disease transmission is still ongoing in Hodeidah and Al-Mahwit governorates of Tihama region as indicated by the anti-Ov16 IgG4 seropositivity among children aged ≤10 years. In Bani Sa'ad, where affected individuals had been regularly targeted with ivermectin over the last 15 years, we found that the anti-Ov16 IgG4 seroprevalence rate was significantly lower among children aged ≤10 years (9.1%; 5/55) compared to those >10 years (24.5%; 37/151), reflecting a possible decline in disease transmission. We also revealed onchocerciasis transmission in districts with unknown previous endemicity for the first time, with rates of 8.0% and 6.1% being found in Al Marawi'ah and As Sukhnah districts of Hodeidah. Large-scale surveys are recommended for mapping of O. volvulus in human and blackfly populations in endemic foci and neighboring untargeted areas of uncertain endemicity as a forward step towards the elimination of the disease from the country.
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Affiliation(s)
- Mohammed A. K. Mahdy
- Tropical Disease Research Center, University of Science and Technology, Sana’a, Yemen
- Department of Parasitology, Faculty of Medicine and Health Sciences, Sana’a University, Sana’a, Yemen
- * E-mail:
| | - Rashad Abdul-Ghani
- Tropical Disease Research Center, University of Science and Technology, Sana’a, Yemen
- Department of Parasitology, Faculty of Medicine and Health Sciences, Sana’a University, Sana’a, Yemen
| | | | - Samira M. A. Al-Eryani
- Department of Parasitology, Faculty of Medicine and Health Sciences, Sana’a University, Sana’a, Yemen
| | - Abdulsalam M. Al-Mekhlafi
- Department of Parasitology, Faculty of Medicine and Health Sciences, Sana’a University, Sana’a, Yemen
| | - Sami A. A. Alhaidari
- National Schistosomiasis and Parasites Control Program, Ministry of Public Health and Population, Sana’a, Yemen
| | - Ahmed A. Azazy
- Department of Laboratory Medicine, Faculty of Applied Medical Sciences, Al-Baha University, Al-Baha, KSA
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Azazy AA, Alhawery AJ, Abdul-Ghani R, Alharbi RA, Almalki SSR. Evaluation of rapid PfHRP-2/pLDH-based tests in diagnosing microscopy-confirmed falciparum malaria in Hodeidah governorate, Yemen. Acta Trop 2018; 178:252-257. [PMID: 29217380 DOI: 10.1016/j.actatropica.2017.12.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 11/29/2017] [Accepted: 12/02/2017] [Indexed: 11/15/2022]
Abstract
Along with the determination of malaria infection rate among suspected patients attending hospitals in Hodeidah governorate, the present study evaluated the accuracy of Plasmodium falciparum histidine-rich protein-2 (PfHRP-2)/parasite-specific lactate dehydrogenase (pLDH)-based rapid diagnostic test (RDT) for the diagnosis of microscopy-confirmed falciparum malaria. An overall malaria infection rate of 19.3% (57/295) among suspected patients attending hospitals was microscopically confirmed. The sensitivity of thin blood films for the detection of malaria parasites was 79.0% compared to thick films and was greatly affected by the parasite density, being 65.0% or less at parasite densities of ≤1000 parasites/μl of blood. Compared to light microscopy, the present study revealed sensitivity levels of 100.0% (95% CI: 92.0-100.0) vs. 94.7% (95% CI: 84.2-98.6), specificity levels of 97.3% (95% CI: 89.8-99.5) vs. 100.0% (95% CI: 93.9-100.0), positive predictive values of 89.9% (95% CI: 88.3-99.0) vs. 100.0 (95% CI: 91.6-100.0) and negative predictive values of 100.0% (95% CI: 93.9-100.0) vs. 98.7% (95% CI: 89.3-98.7) for the PfHRP-2 and pLDH components of SD BIOLINE® RDT, respectively, for falciparum malaria diagnosis. Therefore, the overall accuracy levels of the PfHRP-2 and pLDH components of the investigated RDT for the diagnosis of microscopy-confirmed falciparum malaria are 98.5% (95% CI: 94.6-99.6) and 97.7% (95% CI: 93.5-99.2), respectively.
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Affiliation(s)
- Ahmed A Azazy
- Department of Laboratory Medicine, Faculty of Applied Medical Sciences, Al-Baha University, Al-Baha, KSA, Saudi Arabia
| | - Ali Jamaly Alhawery
- Department of Medical Parasitology, Faculty of Medicine and Health Sciences, Hodeidah University, Hodeidah, Yemen
| | - Rashad Abdul-Ghani
- Department of Medical Parasitology, Faculty of Medicine and Health Sciences, Sana'a University, Sana'a, Yemen; Tropical Disease Research Center, Faculty of Medicine and Health Sciences, University of Science and Technology, Sana'a, Yemen.
| | - R A Alharbi
- Department of Laboratory Medicine, Faculty of Applied Medical Sciences, Al-Baha University, Al-Baha, KSA, Saudi Arabia
| | - Shaia S R Almalki
- Department of Laboratory Medicine, Faculty of Applied Medical Sciences, Al-Baha University, Al-Baha, KSA, Saudi Arabia
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Al-Eryani SM, Al-Mekhlafi AM, Al-Shibani LA, Mahdy MMK, Azazy AA. Toxoplasma gondii infection among pregnant women in Yemen: Factors associated with high seroprevalence. J Infect Dev Ctries 2016; 10:667-72. [DOI: 10.3855/jidc.6638] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 09/19/2015] [Accepted: 10/05/2015] [Indexed: 10/31/2022] Open
Abstract
Introduction: Although toxoplasmosis is an important public health problem, there is scarcity of data on the disease available from Yemen. A cross-sectional survey was conducted in health facilities to determine seroprevalence of Toxoplasma gondii and associated risk factors among pregnant women in Sana’a, the capital city of Yemen. Methodology: A total of 593 pregnant women were included and examined for anti-T. gondii antibodies (Ab) using enzyme-linked immunosorbent assay. Bio and socio-demographic data were collected by pre-tested structured questionnaires through face-to-face interviews. Results: The overall seroprevalence of T. gondii was 45.4% (95% confidence interval: 41%–49%). The prevalence of anti-T. gondii IgG and IgM was 43.7 (95% CI: 40–%48%) and 9.1% (95% CI: 7%–12%), respectively. About 7.4 (95% CI: 6%–10%) of pregnant women were seropositive for both IgG and IgM Abs. Multivariate logistic regression analysis identified the following risk factors for toxplasmosis (IgG and/or IgM): age ≥ 25 years (adjusted OR: 2.02, 95% CI: 1.44–2.84, p < 0.001), rearing cats in the house (OR: 1.75, 95% CI: 1.20–2.55, p = 0.004), and contact with soil (OR: 1.90, 95% CI: 1.32–2.75, p = 0.001). Conclusions: The study reported high seroprevalence among pregnant women in Sana’a, Yemen, with a high proportion of pregnant women having a possibility of acute toxoplasmosis. This highlights the need for including routine screening for T. gondii in pregnant women in the country’s antenatal clinics. In addition, health education on the mode of transmission of toxoplasmosis should be provided for pregnant women in Yemen.
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Abdul-Ghani R, Farag HF, Allam AF, Azazy AA. Measuring resistant-genotype transmission of malaria parasites: challenges and prospects. Parasitol Res 2014; 113:1481-7. [PMID: 24562760 DOI: 10.1007/s00436-014-3789-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Accepted: 01/28/2014] [Indexed: 01/09/2023]
Abstract
Increased gametocytemia in infections with resistant strains of Plasmodium species and their enhanced transmissibility are a matter of concern in planning and evaluating the impact of malaria control strategies. Various studies have determined weekly gametocyte carriage in response to antimalarial drugs in clinical trials. The advent of molecular biology techniques makes it easy to detect and quantify gametocytes, the stages responsible for transmission, and to detect resistant genotypes of the parasite. With the validation of molecular markers of resistance to certain antimalarial drugs, there is a need to devise a simpler formula that could be used with these epidemiological antimalarial resistance tools. Theoretical models for transmission of resistant malaria parasites are difficult to deploy in epidemiological studies. Therefore, devising a simple formula that determines the potential resistant-genotype transmission of malaria parasites should provide further insights into understanding the spread of drug resistance. The present perspective discusses gametocytogenesis in the context of antimalarial treatment and drug resistance. It also highlights the difficulties in applying the available theoretical models of drug resistance transmission and suggests Rashad's devised formula that could perhaps be used in determining potentially transmissible resistant genotypes as well as in mapping areas with high potential risk for the transmission of drug-resistant malaria. The suggested formula makes use of the data on gametocytes and resistant genotypes of malaria parasites, detected by molecular techniques in a certain geographical area within a particular point in time, to calculate the potential risk of resistant genotype transmission.
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Affiliation(s)
- Rashad Abdul-Ghani
- Department of Parasitology, Faculty of Medicine and Health Sciences, Sana'a University, Sana'a, Yemen,
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Al-Shibani LAN, Al-Eryani SMA, Azazy AA, Al-Mekhlafi AM. Cases of hydatidosis in patients referred to Governmental hospitals for cyst removal in Sana'a City, Republic of Yemen. Trop Biomed 2012; 29:18-23. [PMID: 22543599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Hydatidosis is a parasitic infestation caused by Echinococcus granulosus. This disease is endemic in many countries including Yemen. The present review article aims to have a glimpse at the present status of hydatidosis in Yemen. This is the first descriptive study, investigating recorded cases of hydatidosis from the five main governmental hospitals in the capital Sana'a city, over a longer period starting from 2001 and ending in 2008. A total of 796 medical records of patients referred to the five main governmental hospitals in Sana'a city for cyst removal, were studied. Of these cases 482 were females and 314 were males. Their mean age was 30.0 ± 16.9 years. Information regarding the location of the cyst in the body, age, sex and residence of each patient was recorded. A higher infection rate was found in females than males (60.6% and 39.4%, respectively). Single organ involvement was observed in 98.6% cases, among which, the most frequent localizations were the liver (60.8%) followed by the lung (24.7%). Cases of hydatidosis appeared to increase during the period 2001-2008, with the lowest number (n=26) and the highest number (n=140) recorded in 2001 and 2007, respectively. We conclude that the risk of hydatidosis is still high in Yemen, where street or stray dogs move freely down town and the population should be aware about the role of dogs in the transmission of this disease. Hospital records provide a useful indication of infection expressed as annual rate of hospital cases. Finally, the collaboration of Public Health Authorities, the Veterinary Medical Authorities and the Environmental Affairs Authorities is a must to control this disease.
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Affiliation(s)
- Latifa A N Al-Shibani
- Department of Parasitology, Faculty of Medicine and Health Sciences, Sana'a University, Sana'a, Yemen
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Al-Mekhlafi AM, Mahdy MAK, Al-Mekhlafi HM, Azazy AA, Fong MY. High frequency of Plasmodium falciparum chloroquine resistance marker (pfcrt T76 mutation) in Yemen: an urgent need to re-examine malaria drug policy. Parasit Vectors 2011; 4:94. [PMID: 21619624 PMCID: PMC3125383 DOI: 10.1186/1756-3305-4-94] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Accepted: 05/27/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria remains a significant health problem in Yemen with Plasmodium falciparum being the predominant species which is responsible for 90% of the malaria cases. Despite serious concerns regarding increasing drug resistance, chloroquine is still used for the prevention and treatment of malaria in Yemen. This study was carried out to determine the prevalence of choloroquine resistance (CQR) of P. falciparum isolated from Yemen based on the pfcrt T76 mutation. METHODS A cross-sectional study was carried out among 511 participants from four governorates in Yemen. Blood samples were screened using microscopic and species-specific nested PCR based on the 18S rRNA gene to detect and identify Plasmodium species. Blood samples positive for P. falciparum were used for detecting the pfcrt T76 mutation using nested-PCR. RESULTS The prevalence of pfcrt T76 mutation was 81.5% (66 of 81 isolates). Coastal areas/foothills had higher prevalence of pfcrt T76 mutation compared to highland areas (90.5% vs 71.8%) (p = 0.031). The pfcrt T76 mutation had a significant association with parasitaemia (p = 0.045). Univariate analysis shows a significant association of pfcrt T76 mutation with people aged > 10 years (OR = 9, 95% CI = 2.3 - 36.2, p = 0.001), low household income (OR = 5, 95% CI = 1.3 - 19.5, p = 0.027), no insecticide spray (OR = 3.7, 95% CI = 1.16 - 11.86, p = 0.025) and not sleeping under insecticide treated nets (ITNs) (OR = 4.8, 95% CI = 1.38 - 16.78, p = 0.01). Logistic regression model confirmed age > 10 years and low household income as predictors of pfcrt T76 mutation in Yemen P. falciparum isolates. CONCLUSIONS The high prevalence of pfcrt T76 mutation in Yemen could be a predictive marker for the prevalence of P. falciparum CQR. This finding shows the necessity for an in-vivo therapeutic efficacy test for CQ. P. falciparum CQR should be addressed in the national strategy to control malaria.
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Al-Mekhlafi AM, Al-Mekhlafi HM, Mahdy MAK, Azazy AA, Fong MY. Human malaria in the highlands of Yemen. Ann Trop Med Parasitol 2011; 105:187-95. [PMID: 21801497 PMCID: PMC4090792 DOI: 10.1179/136485911x12987676649421] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 02/08/2011] [Accepted: 02/10/2011] [Indexed: 12/28/2022]
Abstract
Between June 2008 and March 2009, a cross-sectional study of human malaria was carried out in four governorates of Yemen, two (Taiz and Hodiedah) representing the country's highlands and the others (Dhamar and Raymah) the country's coastal plains/foothills. The main aims were to determine the prevalences of Plasmodium infection among 455 febrile patients presenting for care at participating health facilities and to investigate the potential risk factors for such infection. Malarial infection was detected in 78 (17·1%) of the investigated patients and was more likely to be detected among the febrile patients from the highlands than among those presenting in the coastal plains/foothills (22·6% v.13·9%; χ(2)=10·102; P=0·018). Binary logistic-regression models identified low household income [odds ratio (OR)=13·52; 95% confidence interval (CI)=2·62-69·67; P=0·002], living in a household with access to a water pump (OR=4·18; CI=1·60-10·96; P=0·004) and living in a household near a stream (OR=4·43; CI=1·35-14·56; P=0·014) as significant risk factors for malarial infection in the highlands. Low household income was the only significant risk factor identified for such infection in the coastal plains and foothills (OR = 8·20; CI=1·80-37·45; P=0·007). It is unclear why febrile patients in the highlands of Yemen are much more likely to be found to have malarial infection than their counterparts from the coastal plains and foothills. Although it is possible that malarial transmission is relatively intense in the highlands, it seems more likely that, compared with those who live at lower altitudes, those who live in the highlands are less immune to malaria, and therefore more likely to develop febrile illness following malarial infection. Whatever the cause of the symptomatic malarial infection commonly found in the highlands of Yemen, it is a matter of serious concern that should be addressed in the national strategy to control malaria.
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Al-Mekhlafi AM, Mahdy MA, A Azazy A, Fong MY. Molecular epidemiology of Plasmodium species prevalent in Yemen based on 18 s rRNA. Parasit Vectors 2010; 3:110. [PMID: 21092097 PMCID: PMC2997089 DOI: 10.1186/1756-3305-3-110] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Accepted: 11/19/2010] [Indexed: 11/12/2022] Open
Abstract
Background Malaria is an endemic disease in Yemen and is responsible for 4.9 deaths per 100,000 population per year and 43,000 disability adjusted life years lost. Although malaria in Yemen is caused mainly by Plasmodium falciparum and Plasmodium vivax, there are no sequence data available on the two species. This study was conducted to investigate the distribution of the Plasmodium species based on the molecular detection and to study the molecular phylogeny of these parasites. Methods Blood samples from 511 febrile patients were collected and a partial region of the 18 s ribosomal RNA (18 s rRNA) gene was amplified using nested PCR. From the 86 positive blood samples, 13 Plasmodium falciparum and 4 Plasmodium vivax were selected and underwent cloning and, subsequently, sequencing and the sequences were subjected to phylogenetic analysis using the neighbor-joining and maximum parsimony methods. Results Malaria was detected by PCR in 86 samples (16.8%). The majority of the single infections were caused by P. falciparum (80.3%), followed by P. vivax (5.8%). Mixed infection rates of P. falciparum + P. vivax and P. falciparum + P. malariae were 11.6% and 2.3%, respectively. All P. falciparum isolates were grouped with the strain 3D7, while P. vivax isolates were grouped with the strain Salvador1. Phylogenetic trees based on 18 s rRNA placed the P. falciparum isolates into three sub-clusters and P. vivax into one cluster. Sequence alignment analysis showed 5-14.8% SNP in the partial sequences of the 18 s rRNA of P. falciparum. Conclusions Although P. falciparum is predominant, P. vivax, P. malariae and mixed infections are more prevalent than has been revealed by microscopy. This overlooked distribution should be considered by malaria control strategy makers. The genetic polymorphisms warrant further investigation.
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Affiliation(s)
- Abdulsalam Mq Al-Mekhlafi
- Department of Parasitology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia.
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Mahdy MAK, Al-Mekhlafi HM, Al-Mekhlafi AM, Lim YAL, Bin Shuaib NOM, Azazy AA, Mahmud R. Molecular characterization of Leishmania species isolated from cutaneous leishmaniasis in Yemen. PLoS One 2010; 5. [PMID: 20862227 PMCID: PMC2942841 DOI: 10.1371/journal.pone.0012879] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Accepted: 08/28/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Cutaneous leishmaniasis (CL) is a neglected tropical disease endemic in the tropics and subtropics with a global yearly incidence of 1.5 million. Although CL is the most common form of leishmaniasis, which is responsible for 60% of DALYs lost due to tropical-cluster diseases prevalent in Yemen, available information is very limited. METHODOLOGY/PRINCIPAL FINDINGS This study was conducted to determine the molecular characterization of Leishmania species isolated from human cutaneous lesions in Yemen. Dermal scrapes were collected and examined for Leishmania amastigotes using the Giemsa staining technique. Amplification of the ribosomal internal transcribed spacer 1(ITS-1) gene was carried out using nested PCR and subsequent sequencing. The sequences from Leishmania isolates were subjected to phylogenetic analysis using the neighbor-joining and maximum parsimony methods. The trees identified Leishmania tropica from 16 isolates which were represented by two sequence types. CONCLUSIONS/SIGNIFICANCE The predominance of the anthroponotic species (i.e. L. tropica) indicates the probability of anthroponotic transmission of cutaneous leishmaniasis in Yemen. These findings will help public health authorities to build an effective control strategy taking into consideration person-to-person transmission as the main dynamic of transmission of CL.
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Affiliation(s)
- Mohammed A K Mahdy
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
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Al-Ghoury ABA, El-Hamshary EM, Azazy AA, Hussein EM, Rayan HZ. HLA class II alleles: susceptibility or resistance to cystic echinococcosis in Yemeni patients. Parasitol Res 2010; 107:355-61. [DOI: 10.1007/s00436-010-1868-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Accepted: 04/01/2010] [Indexed: 11/30/2022]
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Al-Shibani LA, Azazy AA, El-Taweel HA. Cryptosporidiosis and other intestinal parasites in 3 Yemeni orphanages: prevalence, risk, and morbidity. J Egypt Soc Parasitol 2009; 39:327-337. [PMID: 19530632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The epidemiological pattern of cryptosporidiosis and other intestinal parasites were studied among 3 orphanages in Sana'a City. A total of 292 orphans (225 males & 67 females), aged 4-20 years old were recruited. A questionnaire of demographic information, health status and other relevant information was filled out for each one. Fresh stool specimens were processed by wet mount preparation, formalin-ether concentration and MZL stain. Among 292 orphans, the overall parasitic rate was 62.7%. C. parvum showed highest prevalence (24%) followed by G. lamblia (16.8%), E. histolytica /E.dispar (13%), and then E. coli (18.5%). Hymenolepis nana was in 7.2% of children but only 3 cases of Ascaris lumbricoides. The risk of C. parvum was significantly higher in children < or = 10 years of age compared to older ones (OR = 3.86). The risk of other parasites did not differ significantly with orphans' age. Males showed 2.634 risk of C. parvum and 1.657 risk of G. lamblia compared to females with statistically significant difference. Bad personal hygiene was associated with higher risk of cryptosporidiosis (OR = 2.634, CI = 1.483-4.677) but the risk of other parasites was not significant. Diarrhea and abdominal pain were recorded in the three orphans, but without significance associated with parasites, either overall or for individual species but, A. lumbricoides was detected in 3 diarrheic children.
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Affiliation(s)
- Latifa A Al-Shibani
- Department of Medical Parasitology, Faculty of Medicine and Health Sciences, Sana'a University, Sana'a, Yemen.
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Al-Shibani LA, Azazy AA, Alhamd JH. Intestinal parasitosis among apparently healthy workers at restaurants of Sana'a City, Yemen. J Egypt Soc Parasitol 2009; 39:263-268. [PMID: 19530626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A cross sectional study was conducted on randomly selected 303 apparently healthy workers in 58 restaurants in Sana'a City, with ages between 12 to 70 years 22.12 +/- 8.34). A required data were taken through a designed questionnaire and stool samples were collected and examined microscopically by direct wet mount (saline and iodine stained smears) and by formalin ether concentration sedimentation technique. The results showed 72.9% an overall infections rate In a descending order they were E. coli (58.85%), E. histolytica (48.87%), G. lamblia (35.29%), S. man-soni (7.69%), T. trichiura (4.98%), A. lumbricoides (4.07%), H. nana (3.62%), and 0.91% for both E. vermicularis and A. doudenale. Intervention programs including health education, strict supervision of health authorities on workers in restaurants, hotels and other food shops as well as environmental sanitation are required.
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Affiliation(s)
- Latifa A Al-Shibani
- Department of Medical Parasitology, Faculty of Medicine and Health Sciences, Sana'a University, Sana'a, Yemen.
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Azazy AA, Al-Shibani LA, Mohammad AES. Anti-leishmanial polyclonal antibodies to assess the performance characteristics of leishmanial antigen detection ELISA. J Egypt Soc Parasitol 2008; 38:1027-1036. [PMID: 19209783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The polyclonal antibodies raised in rabbits against amastigote antigen extract were purified and fractionated, and IgG class antibodies and from the same antibodies, a peroxidase conjugate (labeled antibodies) reagent were prepared. The antibodies and the labeled antibodies were analyzed for efficacy of the homologous extracted antigens by capture ELISA. The titration curves of the anti-amastigote IgG antibody against extracted antigens showed that both free antibody and corresponding labeled antibody reacted with the original amastigote antigens. Further analysis involved the interaction between the antibody and two leishmanial stages; mammalian amastigote & infective promasitgote by immunoflourescene technique. The strong interaction was not only with surface antigenic components of the stages but also with their internal components. Capture-ELISA system was done to detect specific leishmanial antigens in urine and sera from visceral leishmaniasis patients (VL). Most of the urine samples were positive (90% sensitivity) for leishmanial antigens without cross-reactivity (100% specificity) with any other tested samples from heterologous parasitic infections. But, only 61% sensitivity and 53% specificity were obtained when the capture ELISA was done to detect the specific leishmanail antigens in sera from VL.
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Affiliation(s)
- Ahmed A Azazy
- Department of Medical Parasitology, Faculty of Medicine and Health Sciences, Sana'a University, P.O. Box 14460, Sana'a, Yemen.
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Azazy AA, Nasher ST, Ishaq A, Bin-Muhanna M, Chance ML. Detection of antileishmanial IgG antibodies and Leishmania-specific antigens in sera from Yemeni patients with visceral leishmaniasis. Ann Trop Med Parasitol 2003; 97:689-95. [PMID: 14613628 DOI: 10.1179/000349803225002481] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
As part of an attempt to develop an effective method for the serodiagnosis of visceral leishmaniasis (VL), the sera from 43 Yemeni cases of the disease were screened both for antileishmanial IgG antibodies and for Leishmania-specific antigens. Indirect ELISA and capture ELISA were used to test each serum for the antibodies and antigens, respectively. Sera from patients with diseases other than leishmaniasis (29 for the antibody-detection assays and 42 for the antigen-detection) and from apparently healthy volunteers were also tested. For each type of assay, the threshold for seropositivity was set three standard deviations above the mean absorbance value for the sera from the healthy volunteers. Thirty-seven of the 43 VL sera were found positive for Leishmania-specific IgG antibodies and 37 were found positive for Leishmania-specific antigens. The sensitivities of the antibody- and antigen-detection assays were both therefore 86%. The overall specificity of the antibody-detection ELISA (67%) was, however, slightly higher than that of the capture-ELISA (64%).
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Affiliation(s)
- A A Azazy
- Faculty of Medicine and Health Sciences, Sana'a University, PO Box 14460, Sana'a, Yemen
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Azazy AA, Raja'a YA. Malaria and intestinal parasitosis among children presenting to the paediatric centre in Sana'a, Yemen. East Mediterr Health J 2003; 9:1048-53. [PMID: 16450536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We studied the profile of malaria and intestinal parasitosis among children presenting to the Paediatric Health Centre in Sana'a from January 1998 to December 2000. In stool samples from 9014 children, Ascaris lumbricoides, Entamoeba histolytica, Giardia lamblia and Trichuris trichiura were the most common. Infection with parasites of direct life-cycle were similar in boys and girls. Schistosome infection was significantly higher in boys than girls, but girls were more infected with ascariasis. The only species of malaria parasite found in blood samples from 753 children with suspected malaria was Plasmodium falciparum, with the highest rates in April-June. The majority of positive cases were Yemeni children, but 10.8% were Sudanese or Ethiopian.
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Affiliation(s)
- A A Azazy
- Department of Parasitology, Faculty of Medicine and Health Sciences, Sana'a, Yemen
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Azazy AA, Abdelhamid AH. Indirect haemagglutination (IHA) for the diagnosis of hydatid disease in Yemen. J Egypt Soc Parasitol 2000; 30:407-11. [PMID: 10946502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Antihydatid cyst antibodies from sera of infected Yemeni patients were detected using indirect haemagglutination assay (IHA). Antihydatid cyst antibodies were detected in 34 out of 38 serum samples (89% sensitivity). The specificity of the assay was defined to be 97.0% as cross reactivity only noticed with serum from one patient with Schistosoma mansoni out of 11 Schistosoma positive patients examined. Results were discussed.
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Affiliation(s)
- A A Azazy
- Department of Medical Parasitology, Faculty of Medicine, Sana'a University, Yemen
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Azazy AA, Al-Tiar AS. A study survey on intestinal and blood parasites among school children in Sana'a province, Yemen. Saudi Med J 1999; 20:422-424. [PMID: 27632648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023] Open
Abstract
Full text is available as a scanned copy of the original print version.
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Affiliation(s)
- A A Azazy
- Parisitology Department, Faculty of Medicine & Health Science, Sana'a University, Sana'a, Republic of Yemen
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Azazy AA, Chance ML, Devaney E. A time-course study of circulating antigen and parasite-specific antibody in cotton rats infected with Leishmania donovani. Ann Trop Med Parasitol 1997; 91:153-62. [PMID: 9307657 DOI: 10.1080/00034983.1997.11813125] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Levels of circulating antigen in a group of cotton rats infected with Leishmania donovani were followed over a 28-week period, using a modified, polyethylene-glycol (PEG) ELISA. Circulating antigen could be detected from 1 week post-infection and gradually increased over time. In infected cotton rats treated with a curative dose of Pentostam at 12 weeks post-infection, antigen levels peaked and then declined. Antigen was still detected in some of the treated animals at 28 weeks post-infection. The antibodies used in the PEG-ELISA were also used in a capture ELISA to detect parasite antigens in urine. Urine samples which were positive by capture ELISA were also analysed by western blotting, in an attempt to identify the parasite antigens present. Three components, of 45, 47 and 58 kDa, were detected.
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Affiliation(s)
- A A Azazy
- Faculty of Medicine, Sana'a University, Yemen
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Abstract
Leishmanial antigen in circulating immune complexes (CIC) from sera of cotton-rats experimentally infected with Leishmania donovani and visceral leishmaniasis patients (VLP) was detected using a polyethylene glycol (PEG) enzyme-linked immunosorbent assay (PEG-ELISA). The immune complexes were precipitated in the cold with 12% PEG (average M(r) 6000) and then dissociated with glycine-HCl buffer. The dissociated antigen bound to the plate was then detected by peroxidase-labelled rabbit antibody raised to either amastigotes or to CIC. Serum samples from either controls or patients infected with heterologous organisms were used to define the sensitivity and specificity of the test. Leishmanial antigen was detected in the CIC from all experimentally infected animals (100% sensitivity) and in 22 of 25 of the CIC from VLP (88% sensitivity), using either conjugate. Immunoblotting of PEG-precipitated CIC from infected animals with both rabbit antisera revealed multiple antigen components. Antigens of 40, 42 and 45 kDa appeared to be specifically recognized by both antibodies; the components of 40 and 42 kDa were common to amastigote extracts and CIC from infected animals.
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Affiliation(s)
- A A Azazy
- Biomedical Science Division, Liverpool School of Tropical Medicine, UK
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