Status of imported malaria in a control zone of the United Arab Emirates bordering an area of unstable malaria

Mosquito biodiversity and mosquito-borne viruses in the United Arab Emirates

Background

In the last 50 years, the United Arab Emirates (UAE) has experienced rapid population growth and urbanization. Urbanization is known to influence biodiversity, and there appears to be a link between the emergence of arboviruses and urban growth. Very little is known about the UAE mosquito species richness and dominant vectors. We performed a mosquito survey comparing peri-urban sites in Dubai and Al Ain to a protected, natural site in Fujairah emirate. We measured mosquito biodiversity and species composition, and screened mosquito pools for common arboviruses to measure arbovirus activity in the region.

Results

We report ten species of mosquitoes from the UAE, with highest species diversity in the natural site, a protected wadi near the eastern coast. The predominant mosquito was Culex perexiguus, and was associated with peri-urban habitats. The site with lowest mosquito species diversity but relatively high species richness was the peri-urban site of Al Ain Zoo, where we identified Bagaza virus and Barkedji virus, two flaviviruses, in pools of Cx. perexiguus.

Conclusions

Decreased mosquito biodiversity was associated with increased levels of urbanization. The predominance of two species at peri-urban sites was related to the availability of their larval habitats. Arboviruses were associated with the presence of a single predominant mosquito species, Cx. perexiguus.

Epidemiology of Malaria in the State of Qatar, 2008-2015

Background and Objectives

Imported malaria poses a serious public health problem in Qatar because its population is “naïve” to such infection; where local transmission might lead to serious, life-threatening infection and might even trigger epidemics.

Methods

This study is a retrospective review of the imported malaria cases in Qatar reported by the malaria surveillance program at the Ministry of Public Health (MoPH), during the period between January 2008 and December 2015. All cases were imported and underwent parasitological confirmation through microscopy.

Results

A total of 4092 malaria cases were reported during 2008–2015 in Qatar. The demographic features of the imported cases show that the majority of cases were males (93%), non-Qatari (99.6%), and aged 15 to 44 years (82.1%). Moreover, P. vivax was found to be the main etiologic agent accounting for more than three-quarters (78.7%) of the imported cases. In addition, almost a third (33.1%) of the cases were reported during the months of July, August, and September.

Conclusions

Imported malaria in Qatar has witnessed an increase during the past seven years, despite a long period of constant reduction; where the people most affected were adult male migrants from endemic countries. Many challenges need to be overcome to prevent the reintroduction of malaria into the country.

Cross-border malaria: a major obstacle for malaria elimination

Movement of malaria across international borders poses a major obstacle to achieving malaria elimination in the 34 countries that have committed to this goal. In border areas, malaria prevalence is often higher than in other areas due to lower access to health services, treatment-seeking behaviour of marginalized populations that typically inhabit border areas, difficulties in deploying prevention programmes to hard-to-reach communities, often in difficult terrain, and constant movement of people across porous national boundaries. Malaria elimination in border areas will be challenging and key to addressing the challenges is strengthening of surveillance activities for rapid identification of any importation or reintroduction of malaria. This could involve taking advantage of technological advances, such as spatial decision support systems, which can be deployed to assist programme managers to carry out preventive and reactive measures, and mobile phone technology, which can be used to capture the movement of people in the border areas and likely sources of malaria importation. Additionally, joint collaboration in the prevention and control of cross-border malaria by neighbouring countries, and reinforcement of early diagnosis and prompt treatment are ways forward in addressing the problem of cross-border malaria.

Infectious diseases in the Arabian Peninsula and Egypt

Infectious diseases are important causes of morbidity and mortality globally. Epidemiologically, differences in the patterns of infectious diseases and antimicrobial resistance exist across diverse geographical regions. In this review on infectious diseases in the Arabian Peninsula and Egypt, the epidemiology of tuberculosis, malaria and human immunodeficiency virus (HIV) infections will be addressed. The challenges of the hepatitis C epidemic in Egypt and the epidemiology of this infection across the region will be reviewed. In recent years, we have seen dengue endemicity become established, with major outbreaks in parts of the region. Emerging data also indicate that, across the region, there is an increasing burden of antibiotic resistance, with endemicity in healthcare settings and dissemination into the community. New challenges include the emergence of the Alkhurma haemorrhagic fever virus in Saudi Arabia. The annual Hajj pilgrimage in Saudi Arabia serves as a model for the control of infectious disease in mass gatherings. As most of these countries constantly experience a uniquely dynamic population influx in the form of expatriate workers, tourists, or pilgrims, concerted regional and international collaboration to address these public health concerns in a region that lies at the crossroads for the global spread of infectious pathogens is imperative.

Epidemiology of imported malaria in Qatar

OBJECTIVE

This study estimated the annual incidence of imported malaria in Qatar from 1997 to 2006 and described the epidemiological features of malaria from 2004 to 2006.

METHODS

A retrospective review was conducted of the imported malaria cases in Qatar reported by the malaria surveillance program during the period 1997 to 2006 to estimate annual incidence. Data on 438 malaria cases reported during 2004 to 2006 were analyzed to describe the epidemiological features of imported malaria in Qatar.

RESULTS

The incidence of malaria in 1997 was 58.6/100,000, and since then, it has shown a consistent decline to reach the lowest rate of 9.5/100,000 in 2004. After that the incidence of malaria has increased by more than two times in 2005 and 2006. All 438 malaria cases were contracted as a result of travel to endemic countries, namely India, Pakistan, and Sudan. The majority of cases were male, non-Qatari, and aged 15 years and older. Plasmodium vivax was the main etiologic agent in 40% of cases and most occurred between August and October.

CONCLUSIONS

Imported malaria reported in Qatar has shown an increase in the past 2 years after a long period of constant reduction, and the people most affected were adult male migrants from endemic countries. This group should be targeted by malaria prevention programs.

Status of malaria in the Kingdom of Bahrain: a 10-year review

BACKGROUND

Malaria was eradicated in Bahrain about 20 years ago. However, because of a large immigrant population, cases of imported malaria continued to be seen. This paper presents an evaluation of the data from 1992 to 2001 to assess the levels of indigenous and imported malaria cases and the potential for reemergence of malaria transmission in the country.

METHODS

Epidemiologic and parasitologic data on confirmed malaria cases during the review period were analyzed. Data on vector breeding activity were also analyzed to determine the potential for reemergence of local transmission.

RESULTS

From 1992 to 2001, 1,572 cases of malaria were reported. All were imported malaria cases. There was a consistent decline in the number of cases, from 282 (the peak level) in 1992 to 54 in 2001. Eighty-four percent (1,318/1,572) of infections were contracted as a result of travel to or previous domicile in five countries, namely India, Pakistan, Sri Lanka, Bangladesh and Sudan. Plasmodium vivax was the etiologic agent in 85.6% (1,346/1,572) of cases, with Plasmodium falciparum accounting for 14% (220/1,572). During this period, the percentage of examined breeding sites where Anopheles mosquito larvae were identified remained fairly constant, ranging between 0.05% and 0.1%.

CONCLUSIONS

From 1992 to 2001, there was a consistent decline in the number of imported malaria cases in Bahrain. There were no cases of locally acquired malaria during this period. The low level of vector breeding spots with Anopheles mosquito larvae suggests that the potential for reemergence of local transmission remains low.

Imported malaria in Kuwait (1985-2000)

BACKGROUND

The objective of this study was to document the status of malaria infection and effect of preventive measures on the epidemiologic profile of imported malaria cases in Kuwait during 1985-2000.

METHODS

The study included screening of two groups of individuals for malaria infection by microscopy; (1) all migrant workers from malaria-endemic countries on their first entry to Kuwait; and (2) all suspected malaria cases already residing in the country. The study period was divided into pre-war (1985-1990), postwar (1992-1997) and proactive preventive (1998-2000) periods. During the proactive preventive period, the home countries were also involved in screening for malaria infection in all prospective immigrants to Kuwait.

RESULTS

The annual incidence of malaria cases detected during the pre-war, postwar and proactive preventive periods ranged between 465 and 1,229, 654 and 1,379, and 248 and 393, respectively. Plasmodium vivax infection was detected in 71% of the cases and P. falciparum in 27%. The number of malaria cases detected increased to >1,300 after the war during 1992-1993. However, the number of malaria cases dropped significantly to less than 400 during 1998-2000 (p80%) of malaria patients were young male adults between 21 and 40 years of age. The data on drug resistance were not well defined, due to limited testing.

CONCLUSION

This study suggests that the proactive preventive program to screen all prospective immigrants for malaria infection in their home countries significantly reduced the numbers of imported infections to <400 cases/year, a drop of 52.6%. In addition, it also identified a group of settled immigrants, the majority of whom were at high risk for acquisition of malaria infection during their visit to home countries. There is an urgent need to target this group for prevention strategies such as education/information and other preventive measures against malaria infection.

Drug-resistant Plasmodium falciparum infection in immigrants and non-immune travellers

OBJECTIVE

To detect the incidence of drug-resistant Plasmodium falciparum malaria infection in immigrants and travellers in non-endemic Kuwait.

METHODS

Over a period of 3 years, July 1995 to September 1998, 1352 malaria patients were enrolled in the study. Of these, 1293 were immigrants from countries where malaria is endemic and 59 were non-immune travellers with a recent history of travel to these countries. The in vitro drug sensitivity was determined in 892 patients.

RESULTS

In all, 892 of 1352 (66.0%) P. falciparum isolates were successfully cultured in vitro for drug sensitivity and 419 (47.0%) isolates showed in vitro resistance to chloroquine or mefloquine. Fifty-six (13.4%) isolates were resistant to both drugs. Chloroquine resistance was observed in > 70% of the isolates from Africa and India followed by Pakistan (39.9%) and Bangladesh (35.9%). The resistance to mefloquine ranged from 26.2% in isolates from Sri Lanka to 47.5% in isolates from African countries.

CONCLUSION

The study highlights the important trend in drug resistance in P. falciparum malaria in immigrants from south-east Asian and African countries.

Seroprevalence of antibodies to repetitive domains of Plasmodium vivax circumsporozoite protein in United Arab Emirates children

The aim of this study was to determine the exposure of child citizens of the United Arab Emirates (UAE) to Plasmodium vivax, and to elucidate if it was related to place of residence or previous international travel to malaria-endemic areas. Blood samples were collected from 1010 primary schoolchildren resident in 7 out of 9 districts of the UAE during October and November 1999. Plasma samples were tested for antibodies against MAP4 (DGQPAGDR)3P2P30, a multiple antigen peptide containing the repeat amino acid sequences of P. vivax circumsporozoite protein (CSP), conjugated to 2 T-helper epitopes, P2 (QYIKANSKFIGITE) and P30 (FNNFTVSFWLRVPKVSASHLE) from tetanus toxin. For confirmation of P. vivax-specific reactivity, positive samples were further tested against (AGDR)6, a synthetic peptide containing 6 copies of a protective epitope within the CSP, and against a recombinant CSP, designated as NS1(81)V20. Results indicated that 3.3% of the children were seropositive. The seropositivity rates differed significantly in relation to place of residence, whereas travel outside the UAE did not significantly affect the exposure rates to P. vivax.

Re-emerging Plasmodium vivax malaria in the Republic of Korea

Plasmodium vivax malaria, which was highly prevalent in the Republic of Korea, disappeared rapidly since 1970s. However, malaria re-emerged with the first occurrence of a patient in 1993 near the demilitarized zone (DMZ), the border between South Korea and North Korea. Thereafter, the number of cases increased exponentially year after year, totaling 6,142 cases (6,249 if United States Army personnels were included) by the end of 1998. Interestingly enough, the majority of cases (3,743; 61%) was soldiers aged 20-25, camping around the northern parts of Kyonggi-do or Gangwon-do (Province) just facing the DMZ. Among 2,399 civilian cases, 1,144 (47.7%) were those who have recently retired from their military services in the northern parts of the two Provinces. The re-emerging malaria characteristically revealed a combination type of short and long incubation periods with predominance of the long type. The course of illness was relatively mild, and the treatment was successful in most patients. Vector mosquitoes are Anopheles sinensis and possibly A. yatsushiroensis. Wide-scale preventive and control measures should be operated to eradicate this re-emerging disease. It has been suggested by many authors that the initial source of the re-emerging malaria was infected mosquitoes which had flown from the northern part of the DMZ.