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REVIEW ARTICLE
Year : 2022 | Volume
: 59
| Issue : 2 | Page : 127-138
Vector-Borne diseases in Egypt: Present status and accelerating toward elimination
Safaa M Eassa1, Ekram W Abd El-Wahab2
1 Tropical Health Department (Division of Parasitology and Medical Entomology), High Institute of Public Health, Alexandria University, Egypt
2 Tropical Health Department (Division of Tropical Health), High Institute of Public Health, Alexandria University, Egypt
Correspondence Address:
Ekram W Abd El-Wahab
High Institute of Public Health, Alexandria University, 165 El Hor reya Road, 21561 Alexandria
Egypt
Safaa M Eassa
High Institute of Public Health, Alexandria University, 165 El Hor reya Road, 21561 Alexandria
Egypt
Source of Support: None, Conflict of Interest: None
CheckDOI: 10.4103/0972-9062.321759
Vector borne diseases (VBDs) remain one of the greatest dangers to global health. At least seven VBDs of public health concern are prevalent in Egypt, including schistosomiasis, fascioliasis, lymphatic filariasis, leishmaniasis, malaria, dengue, and Rift Valley fever. Although many of these diseases are preventable by using evidence-based protective measures, VBD expansion patterns over the past few decades pose a significant challenge for modern parasitology and tropical medicine. In their action plan, Egypt did not identify populations at risk of VBDs. Egypt intends to improve its regional and international communication to identify pathogens and infections and develop “One Health”- compliant preparedness and prevention strategies. However, cross-border collaborations are required for the control of VBDs. In this context, we provide a situational analysis and comprehensive review of the epidemiological data on Egypt’s most prevalent VBDs based on an exhaustive search of the major electronic databases and literature from 1950 to 2019. We identified the gaps in Egypt’s preparedness for vector-borne disease threats, including adaptation documents, surveillance and monitoring, environmental management, and preparations for the health system. There is a lack of implementation of an integrated vector management strategy that integrates chemical, environmental, and biological control as well as health education. This necessitates cross-sectoral coordination and community involvement to improve vector control activities and the use, storage, and disposal of pesticides.
Keywords: Preparedness; Vector-borne diseases, Egypt
An overview of vectors and vector-borne diseases
Vectors are living organisms that can spread infectious diseases from one individual to another (or between animals). Numerous of these vectors are bloodsucking insects that consume disease-causing microorganisms from an infected host (human or animal) and then inject them into their next victim during their next blood meal. Vector-borne diseases (VBDs) are communicable human illnesses or infections transmitted by vectors such as mosquitoes, sandflies, ticks, bugs, flies, fleas, lice, and some freshwater aquatic snails [Table 1].
Table 1: Common vectors, vector-borne diseases and their modes of transmissionVBDs represent more than 17% of all infectious diseases[1],[2],[3]. VBDs are a major public health concern in most tropical and subtropical regions, as well as an emerging threat in some developed nations. Each year, approximately 700,000 people are killed by malaria, dengue fever (DF), schistosomiasis, human African trypanosomiasis, leishmaniasis, Chagas disease, yellow fever, and Japanese encephalitis. These diseases are more prevalent in tropical and subtropical regions, and they affect the poor disproportionately. Since 2014, outbreaks of dengue, malaria, Chikungunya, yellow fever, and Zika have plagued communities, claimed lives, and overwhelmed health systems in numerous nations. The distribution of VBDs is affected by demographic, environmental, and social factors. Furthermore, international travel, global trade, unplanned urbanization, and environmental challenges such as climate change can all affect pathogen transmission, extending or intensifying transmission seasons or causing diseases to emerge in previously unexplored regions. Variations in agricultural practices caused by changes in temperature and precipitation can affect the spread of VBDs. The expansion of urban slums, which lack reliable piped water and proper solid waste management, exposes vast numbers of city dwellers to the risk of mosquito-borne viral infections. These characteristics affect vector populations and the transmission patterns of disease-causing pathogens[2],[3].
We conducted a situational analysis and a comprehensive review of the epidemiological data of major VBDs in Egypt between 1950 and 2019 by searching the major electronic databases (PubMed, EMBASE, Science Direct, Ovid, and Google Scholar) and gray literature (CDC websites). The retrieved sources were imported into the EndNote reference manager, and 58 duplicated studies were carefully removed. We included English language research articles, literature reviews, meta-analyses, and situation reports. The relevance of all titles and abstracts was evaluated, and the full texts of potentially eligible articles were reviewed.
VBDs posing public health threats in Egypt and recent outbreaks
At least seven VBDs of public health concern are prevalent in Egypt, including schistosomiasis, fascioliasis, lymphatic filariasis, leishmaniasis, malaria, and Rift Valley fever [Figure 1][4],[5],[6],[7],[8],[9],[10],[11],[12]. However, many of these diseases are preventable by using protective measures supported by evidence. World Health Organisation (WHO) collaborated with the Egyptian Ministry of Health and Population (MoHP) to conduct a vector control needs assessment and develop an action plan to strengthen national capacity in integrated vector management, vector mapping, resistance monitoring, and prudent pesticide management for public health. The WHO provides MOHP with technical assistance in expanding vector mapping and increasing vector risk surveillance in high-risk areas[13].
Figure 1: Distribution of A. vectors and B. vector-borne diseases in Egypt. Egypt map shows different Egyptian provinces including; (1) Alexandria, (2) El- Beheira, (3) Kafr El-Sheikh, (4) El-Gharbia, (5) El-Menofia, (6) El-Qalubia, (7) El-Sharquia, (8) El-Dakahlia, (9) Damietta, (10) Port Said (11) El-Ismailia (12) El-Suez, (13) Cairo, (14) El-Faiyoum, (15) Beni-Suef, (16) El-Menia, (17) Giza, (18) Marsa Matrouh, (19) Assiut, (20) Sohag, (21) Qena, (22) Luxur, (23) Aswan, (24) Red Sea, (25) New Valley, (26) North Sinai, (27) South Sinai. Color dots represent the distribution of the different vectors and vector-borne diseases.Schistosomiasis
Schistosomiasis is a parasitic infection caused by blood flukes (trematode worms) of the genus Schistosoma. People become infected when the larval forms of the parasite ejected by freshwater snails penetrate the skin via contact with infested water. Schistosoma mansoni, S. japonicum, S. mekongi, S. intercalatum, and S. haematobium[14] cause the intestinal and urogenital forms of schistosomiasis, respectively. Schistosomiasis primarily impacts rural and impoverished communities, especially agricultural and fishing communities. Women who perform domestic tasks in schistosomiasis-infested water, such as washing clothes, are also susceptible to developing female genital schistosomiasis. Children are especially vulnerable to infection due to poor hygiene and contact with contaminated water)[15].
Once highly endemic and affecting many people, schistosomiasis is now low-endemic throughout the country. As the prevalence of S. haematobium declines across the nation, particularly in the Nile Delta, a new pattern of schistosomiasis infection has been observed. The WHO collaborates with the MoHP and the National Schistosomiasis Control Programme to reduce morbidity and infection prevalence in all affected areas through the successful implementation of a strategy based on repeated, regular anti-helminthic treatment of school-aged children, the high-risk population. The primary school health system and other ongoing health or education programs guarantee the provision of appropriate care[13]. Between 1989 and 1996, the MoHP diagnosed and treated approximately 2.5 million cases of schistosomiasis annually. During this period, more than 20 million doses of praziquantel were administered, and annual reports in Egypt indicated that the prevalence of S. haematobium and S. mansoni was less than 0.5% between 2009 and 2012 and less than 0.2% between 2013 and 2016[16]. The identification of ‘persistent hotspots’ among treated villages within control districts revealed the importance of interrupting both snail-to-human and human-to-snail transmission to completely prevent new infections. In reality, the annual mass drug administration can reduce morbidity, but it rarely results in a considerable reduction of the local parasite reservoir[17].
Moving from control toward schistosomiasis elimination in Egypt
Following the progress made in reducing the burden of schistosomiasis to approximately 0.2% by the end of 2016, in 2014, the WHO supported the MoHP in the development of an eight-year plan for the elimination of schistosomiasis in the country. The MoHP has initiated a program to eradicate schistosomiasis by 2020. The campaign began in 2017 with the distribution of 14.5 million praziquantel tablets, an insecticide for the control of snails and cercaria-infested water, and the treatment of 6 million school children and citizens at a total cost of 40 million pounds, including praziquantel, pesticide, and the cost of health teams and watercourse treatment in collaboration with the Environment Agency and the WHO[18]. The plan included four primary strategies: mass therapy, snail control, environmental sanitation, health education, and behavior modification. Monitoring, prolonged treatment, and continuous examinations of infected cases, particularly school-aged children, are guaranteed in Egypt’s villages with a prevalence of more than 3% and persistent hotspots[16].
In order to prevent resurgence and recrudescence, new strategies based on sensitive surveillance tools must be implemented to maintain low endemicity and ultimately eliminate diseases. The school-based deworming campaign must continue in highly affected regions, particularly Upper Egypt[13].
Fascioliasis
Human fascioliasis was considered a secondary disease until the mid-1990s. Due to the vast colonization capabilities of its vector species of lymnaeid snail hosts and infectious agents, this old disease has great potential for propagation. Fascioliasis is emerging or re-emerging in many countries, with an increase in both intensity and geographic distribution. The WHO (PVC, CPE, Geneva Headquarters) has agreed to launch a global initiative with two primary axes to combat human fascioliasis: A) transmission and epidemiology investigations; B) control activities, primarily triclabendazole (Egaten®), a highly effective anthelmintics administered in a single dose. The WHO has recently added fascioliasis to its list of neglected tropical diseases. Fascioliasis is a zoonosis that occasionally affects humans in addition to cattle, camels, and donkeys. The disease is prevalent in many villages in the Nile Delta, but data on the disease’s overall burden in Egypt is lacking due to the wide variation in infection rates observed in epidemiological studies. Human infection generates significant hepatic pathological sequences, which contribute to the Egyptian population’s prevalence of liver disease[19].
Malaria
Infection with a protozoan of the genus Plasmodium causes malaria, which is transmitted by biting an infected female Anopheles mosquito. Based on the secondary structure and sequence of ITS2- rDNA, Anopheles pharoensis was determined to be an important vector throughout Egypt, particularly in the Delta; An. sergenti is the primary vector in the Western Desert Oases, An. multicolor in Al-Fayoum, An. stephensi in the Red Sea Coast, and An. superpictus in Sinai[20].
Despite the influence of social, environmental, and behavioral factors, climatic conditions play a significant role in malaria transmission[21]. Since 1998, the malaria control program has recorded no indigenous cases of malaria in Egypt[22]. However, imported cases, primarily from Sub-Saharan Africa, continue to be reported frequently and pose a significant risk. Zaher et al. (2007) documented 16 cases of malaria at the Almaza Military Fever Hospital. These included 9 (56.2%) imported cases of Plasmodium falciparum and 7 (43.8%) locally acquired cases of P. vivax between October 2003 and July 2004[23]. El-Bahnasawy et al. evaluated the clinical and parasitic status of malaria as a cause of fever in patients admitted to Military Fever Hospitals in 2010. These included 36 patients, of whom 20 had already been diagnosed with malaria and were recruited from the African Peacekeeping Mission Forces, as well as 16 cases of prolonged fever from diverse regions of Egypt. In 2014, 14 malaria cases were reported in Egypt. However, each case was imported without any local transmission[7]. Due to the presence of dominant or potentially significant malaria vectors in the region, global climate change raises the possibility of a limited reintroduction of malaria in countries where it had previously been eradicated[24]. In 2014, an outbreak of malaria was reported in Aswan, providing strong evidence that the disease is re-emerging[9]. Numerous factors contribute to the re-emergence of malaria, including imported cases (infections acquired outside and brought into a national territory with the origin of imported cases being traceable to a known malarious area) carrying infection of local Anopheline spp., continuous movement of populations between Aswan governorate and Sudan, as well as the influx of large populations from Africa and Asia to Egypt for educational and religious purposes, and the environmental changes brought by El Salam canal water-sources development projects in Toshka district project[21]. However, since 2014, there have been no locally-transmitted cases of malaria in Egypt[25].
In Al-Fayoum, Bassiouny et al. (1999) conducted a longitudinal entomological study over the course of one year in Kafr Fazara village, Sinnuris District. They discovered that An. sergenti was the most prevalent species, followed by An. multicolor and An. pharoensis. They concluded that only the mean monthly temperature, not relative humidity or wind speed, significantly affected larval breeding. The P. falciparum transmission season extended to more than eight months per year, which could explain the persistence of malaria[26]. Dahesh and Mostafa (2015) re-evaluated malaria in Al-Fayoum and reported that out of 2044 examined individuals (0.68%) were passive cases, i.e., returning from Sudan and seeking treatment at Al-Fayoum malaria units. The examination of the stained thick films obtained from MOHP revealed that nine out of fourteen passive cases (64.2%) were positive, three of which were P. falciparum (33.3%) and the remainder (66.7 %) were P. vivax[27].
The WHO and MoHP will collaborate to respond promptly to malaria threats. The Malaria Surveillance and Information System, malaria notification, and the capacity of public and private sector health workers to diagnose and treat malaria are being strengthened. The WHO is assisting the MoHP in expanding vector mapping and enhancing malaria vector risk surveillance in malaria hotspots. The 2016–2020 Eastern Mediterranean Regional Action Plan for Malaria Control and Elimination was developed with the WHO Regional strategies and frameworks in mind, including the Integrated Vector Management and Public Health Pesticides management frameworks. Regional Action Plan goals, objectives, targets, and approaches are consistent with the Global Technical Strategy (GTS) 2016–2030. In May 2015, the World Health Assembly approved the Global Technical Strategy for Malaria 2016–2030. It provides a comprehensive logic framework that countries can use to expedite malaria eradication. The plan will reduce malaria incidence and mortality rates by at least 90% by 2030. It highlights the importance of using high-quality surveillance data for decision-making and the need for universal coverage of key malaria therapies for all at-risk groups. Additionally, it identifies the areas where new solutions will be required to meet the objectives and provides an estimate of the global implementation cost. In order to ensure common goals and complementarity, the WHO strategy was developed in close collaboration with the Roll Back Malaria Partnership’s Action and Investment to Defeat Malaria 2016–2030 for a Malaria-Free World[28].
Lymphatic filariasis
Lymphatic filariasis is a crippling illness that has afflicted Egypt since the pharaohs’ reign and counts as the second leading parasitic cause of disability. In 2004, the disease was most prevalent in the Nile Delta region. The WHO’s approach to eradicating lymphatic filariasis entails two primary activities: halting parasite transmission through mass drug administration campaigns and providing appropriate case management for disease-affected individuals. The population will be subjected to this technique for at least five years, except children under the age of two, pregnant women, and the extremely ill. Vector control with anti-larval sprays at weekly intervals, biological control with larvivorous fish, environmental engineering with source reduction and water management, and information, education, and communication activities to stop disease transmission in affected areas. Egypt is the first large endemic country in the world to complete a countrywide five-year campaign. Egypt is the first country in the WHO in Eastern Mediterranean Region and the last country in the world to declare that lymphatic filariasis is no longer a threat to public health. Egypt’s success is the result of nearly two decades of sustained control and preventative efforts (including mass population chemotherapy) and surveillance in affected/at-risk regions. However, ongoing mass drug administration activities and post-mass drug administration monitoring are indispensable. The mapping of chronically affected communities is complete, and program operations are now centred on these areas. The WHO and the MoHP collaborate to strengthen the epidemiological surveillance capacity, which is essential for monitoring and evaluating the incidence of disease and the impact of mass medication administration initiatives[29]. New diagnostic methods, such as sandwich ELISA with paramagnetic nanoparticles, have been developed for detecting W. bancrofti infection in humans, thereby creating new opportunities for halting the transmission and eradicating the disease[30]. Chronic lymphatic filariasis must be alleviated through additional efforts. The eradication objective can be attained with increased political commitment and consistent program initiatives[13].
Dengue fever
Throughout its history, Egypt has experienced multiple outbreaks of dengue. The first epidemic occurred in the late 18th century, followed by others in the 19th century up until the 1940s, after which there was a significant decline in prevalence. During World War II, the intensive use of DDT, a potent pesticide, to combat malaria and typhus among civilians and military personnel led to a decline in the Aedes aegypti vector population. However, other species, such as Aedes detritus and Ae. caspius are still prevalent in many governorates of Egypt[31]. In most tropical nations, epidemics wreak havoc on the population, health systems, and economy. The development and spread of dengue viruses pose a pandemic risk. Over the past 50 years, the incidence of DF has multiplied by 30. In more than 100 endemic countries, 50–100 million new infections and 20,000 deaths are predicted to occur annually. Accordingly, WHO designed a strategy for its prevention and control that relies on five technical elements: (i) diagnosis and case management, (ii) integrated surveillance and outbreak preparedness, (iii) sustainable vector control, (iv) future vaccine implementation, and (v) basic, operational and implementation research enabling factors for effective implementation, such as advocacy and resource mobilization, partnership, coordination and collaboration, and communication[32].
In 2011, it was reported that two cases of dengue virus infections in Italy had been imported from South Egypt[33]. In Aswan, Heikal et al. (2011) reported the reappearance of Ae. aegypti[34]. The presence of Ae. aegypti was reported along the border between Sudan and Toshka and was linked to arbovirus activity in Sub-Saharan Africa[35]. Egypt experienced a DF epidemic in the Dayrout district of the Assiut governorate on October 20. In that year, the Dayrout Fever Hospital admitted 253 cases of acute febrile illness, but there were no additional complications or fatalities. Authorities were notified; blood, serum, and oropharyngeal swabs were collected; and positive dengue virus test results were reported. According to the investigation, the mosquito had proliferated by breeding in traditional Egyptian sun-baked clay water containers known as “Zeirs” by the villagers, which are used to store drinking water.
In 2017, two cases of DF were imported to Moscow from the Egyptian city of Hurghada, where DF is not considered endemic[36]. Six additional dengue cases among returning tourists from Belgium, Austria, and Germany[37]. In October 2017, the health department of the Red Sea governorate reported a DF outbreak in El-Qoseir, a city located 145 km south of Hurghada. According to preliminary results, between 1200 and 2500 people were infected. During the ongoing outbreak, these two locations, namely Hurghada and Al-Qoseir, were monitored to collect both adult and larval mosquitoes. In addition to Culex pipiens, larvae and adults of Aedes spp. were identified morphologically as Ae. aegypti in both cities, indicating the re-establishment of this vector species in Egypt[38]. The MoHP announced that DF had caused an epidemic in the Red Sea governorate, where thousands of people have been diagnosed with the virus. According to non-governmental organizations (NGOs) active in the city, most of those affected were children and the elderly. A cluster of ten DF cases has also been identified in the Hurghada fishing region. Since the disease was in its early stages, most reported events were of mild -to -moderate severity, and patients were treated within two to seven days. According to a statement issued by the MoHP in October 2017, only one fatality involving a 63-year-old male was reported. In response, the MoHP developed a comprehensive plan to combat the spread of the virus, which included the deployment of a national team of experts, including field epidemiologists, entomologists, sanitation, and laboratory personnel, to the affected city and its surrounding villages to conduct epidemiological investigations and implement the necessary control measures. Field investigations were conducted to assess the likelihood of the reintroduction of Ae. aegypti into Egypt. From 12 to October 18, 2017, daily sampling was conducted to capture both adult (via gravid traps) and larval (via dipping) stages. This incursion could be explained by one of two scenarios: infected Ae. aegypti could have originated from Saudi Arabia via ships crossing the Red Sea or from Sudan via land transport. This conclusion supports the enhanced surveillance of Ae. aegypti and other vector species, such as the currently expanding Ae. albopictus. Because of the species’ re-emergences, Egypt is once again at risk of arbovirus transmission, including dengue, Chikungunya, Zika, and yellow fever viruses. In order to prevent epidemics, national and international vector control and immunization programs should be implemented. All visitors to mosquito-transmission regions should cover exposed skin and use insect repellents to avoid mosquito bites[38]. In the absence of a low-cost, effective dengue vaccine, the most effective method to manage dengue is to monitor outbreaks and enhance vector control measures. In response to the epidemic, the MoHP has defined a case description for DF and distributed it to physicians in affected cities. Additionally, diverse training was provided to all healthcare professionals to enhance their capacity for early patient diagnosis and treatment. Currently, surveillance is being conducted in the neighboring villages and districts to identify any potential threats and effectively manage cases to prevent further spread.
Rift Valley fever
In 1977, an explosive outbreak of Rift Valley fever was reported in Egypt; the virus was believed to have been introduced via infected livestock trade along the Nile irrigation canal. The Egyptian MoHP reported 148 cases in 2003, including 27 deaths.
West Nile fever
During the 1950s, infections with the West Nile fever virus (WNV) were reported in Egypt. Since 2010, 10 distinct research locations have been reported in the country. The total sample size was reasonably representative of the population of interest (i.e., more than 1000). During 2013–2014, the seroprevalence of WNV in the general population (median prevalence = 55%) and the prevalence of WNV-specific antibodies in the general population were documented (1–61 %). Infection was detected in the primary vector Culex pipiens s.l. as well as various other vector species, including Cx. antennatus, Cx. perexiguus, and Argas reflexus hermannii. As a result, more epidemiological studies on the human, reservoir, and vector dimensions/aspects of the virus occurrence and distribution are needed to pinpoint the geographic distribution of the virus reservoirs and their infection status for targeted prevention and eradication efforts. Furthermore, surveillance capacity at the national and regional levels should be built or enhanced to effectively monitor WNV infection[39]. A prospective cohort study to determine the seroprevalence and incidence of human and West Nile virus infection in Egypt provided substantial evidence for the prevalence and transmission of this virus in indigenous populations. Human seroprevalence rates ranged from 1% to 35%, and seroconversion rates ranged from 7% to 18%, indicating that during the research period, WNV was actively circulating in various regions of Egypt and causing febrile illness in a significant proportion of the population[40].
Zika virus
Since its discovery in the Ugandan forests in 1947, the Zika virus has spread to several African and Asian countries, including Egypt, between 1947 and 1951. Even though no Zika cases have been reported in the Eastern Mediterranean region, the vector mosquito species Ae. aegypti is present in the region, including Egypt, so continued vigilance remains crucial[41]. There is currently no vaccine or medication available to prevent infection with the Zika virus. In order to prevent Zika virus infection, it is essential to avoid mosquito bites during the day and early evening. WHO is assisting nations in preventing and managing problems in accordance with the four key objectives of the Zika Strategic Response Plan: detection, prevention, care and support, and research[41].
Leishmaniasis
Leishmaniasis is a vector-borne disease caused by protozoa of the genus Leishmania that is transmitted through the bites of infected female Lutzomyia and Phlebotomine sandfly species (papatasi and segenti). Both Phlebotomus papatasi and Phlebotomus segenti can circulate in Northeastern Egypt, as indicated by the mapping of suitable habitats for each species of sand fly[4]. Sinai has endemic foci of cutaneous leishmaniasis caused by Leishmania major (Hamadto et al., 2007). In 2008, 471 cases of cutaneous leishmaniasis were reported in Egypt, but the true number was estimated to be in the range of 1300–2200, thus considered underreporting[42]. In contrast, five governorates of Egypt have reported isolated cases of infantile visceral leishmaniasis[35]. There is an immediate need for improved surveillance systems, particularly for high-risk foci targeting intensive control or elimination.
Tick-borne diseases
The number of epidemiologically significant diseases transmitted by ticks has expanded dramatically over the past several decades worldwide. According to reports, three human cases of Crimean-Congo hemorrhagic fever (CCHF) have been identified. One case was discovered at the Almaza Fever Hospital, while the other two were discovered in the Gharbia Governorate. Health and veterinary authorities must address the prevalence of CCHF in regional nations and the global distribution of tick-vector (Hyalomma spp)[43] including Egypt. Borrelia burgdorferi, the spirochete that causes Lyme disease, was found in stray dogs in which Rhipicephalus sanguineus is the only identified tick species[44], according to a study. Although this species of tick has not been considered the primary vector for B. burgdorferi (Ixodes), investigations suggest that Rhipicephalus sanguineus may be implicated in the epidemiology of B. burgdorferi infection[44],[45]. This information is useful and may have epidemiological significance in terms of tracking the spread of a pathogen, identifying potential zoonotic risk, and adopting preventative and intervention strategies such as immunization and control programs, which are not currently used in Egypt. It is essential to increase knowledge of Lyme borreliosis among Egyptian veterinarians and physicians to develop a laboratory capacity for Lyme borreliosis diagnosis in veterinary and infectious disease facilities[44]. The capacity of the soft tick, Ornithodoros savignyi, and the hard tick, Rhipicephalus (formerly Boophilus annulatus), to serve as carriers for new genotypes of Borrelia and Babesia[46] was determined in a 2017 study conducted in Egypt.
Plague
A plague is a zoonotic disease that continues to pose a grave threat to humanity. A resurgence of the plague in Egypt should not be ruled out, given the presence of putative natural foci, global climate change, and the threat posed by some neighboring nations, notably Libya. New towns and urbanization may contribute to the reemergence of the plague from possible natural foci if the plague is prevalent. Particularly in the western half of Egypt, surveillance should be maintained to monitor the presence of potential natural foci and the spread of the plague that may result from environmental effects. Prevention measures should include surveillance of potential natural foci, rodent and insect eradication campaigns, public health education, vaccination, and genetic identification of Y. pestis strains[47]. The first plague epidemic was recorded in Egypt in c. 541 and reappeared multiple times in the nineteenth century. Since 1947, there have been no endemic foci and no cases of plague in Egypt[47],[48], but there is every possibility that it could reappear. During the 1947 Alexandria epidemic, the use of DDT and other control methods significantly decreased flea indices[47],[49]. Fifty years later, DDT resistance was reported in the Pulex irritans (human flea) and Xenopsylla cheopis (rat flea)[50] populations of Egypt. In Egypt’s Cairo province, the effectiveness of malathion, chlorpyrifos, and deltamethrin against the oriental rat flea, Xenopsylla cheopis, and other rodent species was evaluated. In this regard, deltamethrin was more effective against fleas than malathion and chlorpyrifos, as evidenced by their respective LC50 values of 0.1%, 1.0%, and 1.9%, respectively[51].
Louse-borne bacterial pathogens
In Egypt, Pediculus humanus Linnaeus remains a problem[52], although the epidemic typhus has not posed a significant threat recently. The Egyptian populace is at risk of contracting trench fever, louse-borne relapsing fever, or epidemic typhus because of the prevalence of these diseases in neighboring African countries with refugee populations. According to the data, both urban and domestic animals in Egypt are infected with harmful or potentially pathogenic[53] bacteria.
Preparedness and “One Health” strategy for effective vector control
In modern parasitology and tropical medicine, the rapid spread of extremely aggressive arboviruses, parasites, and bacteria, as well as the emergence of resistance in pathogens and parasites, as well as their arthropod vectors, pose significant threats to public health. Malaria, dengue, West Nile, Chikungunya, and Zika virus, in addition to other arboviruses such as St. Louis encephalitis and Japanese encephalitis, necessitate environmentally friendly vector control strategies. However, research into mosquito vector control is hindered by a lack of environmentally friendly and highly effective insecticides and the limited efficacy of most biocontrol measures currently used[54]. The importance of the ‘One Health’ concept was demonstrated by mosquito control programs conducted over the past few decades. Indeed, according to One Health, human health is inextricably linked to animal and environmental health[55]. This strategy’s primary objective is to encourage collaboration between other disciplines to achieve the greatest possible health benefits for humans, animals, and the environment[56],[57]. [Figure 2] depicts a logical framework for preparedness and “One Health” strategy for effective vector control in Egypt[61].
Figure 2: Logical framework for preparedness and “One Health” approach for vector control in Egypt.The gap between what is and what needs to be done in Egypt
A report from the WHO (2015) also illustrates the disparities between national adaptation measures[58]. In the Mediterranean region, eight topics, including governance, vulnerability, adaptation strategies, mitigation, strengthening health systems, raising awareness and building capacities, green health services, and sharing best practices, are used to evaluate countries with significant adaptation strategies or policies such as Egypt[59]. Egypt has developed policy frameworks and adaptation plans or initiatives to mitigate the new risks posed by VBDs because of climate change. It discusses the four categories of examined policy instruments: environmental management, public education, monitoring and surveillance, and health system preparedness. Egypt intends to combine environmental data (vectors) and health data to assess disease outbreak patterns (morbidity and mortality). However, there is still work to be done in Egypt’s plan for preventing VBDs. More particularly regarding the identification of at-risk populations, the improvement of regional and international communication, the identification of pathogens, the development of preventive strategies, and the improvement of environmental management by using a vigilance plan for the thorough inspection and quarantine of products originating from endemic zones. It is crucial to strengthen the health system to conduct risk assessments, develop early warning systems, and implement rapid response plans for vector management. Health professionals, epidemiologists, and practitioners should receive a multidisciplinary education with a global perspective in VBDs, entomology, and tropical medicine. Public education and awareness campaigns are an important consideration for Egypt’s adaptation policy to encourage public participation and engagement in policy-making and support the implementation of control programs[60],[61],[62][Table 2].
Table 2: The gap in vector control strategy in Egypt: what is done in Egypt and what is needed to be doneEthical statement: Not applicable
Conflict of interest: None
Key message
Egypt is threatened by numerous vector-borne diseases.In Egypt, there is a gap between what has been done and what needs to be done in terms of readiness for vector-borne disease threats.In Egypt, the national policy for vector control services relies primarily on chemical control without incorporating other environmental, biological, or health education control methods.Implementing an integrated vector management strategy necessitates intersectoral coordination and community involvement to effectively conduct vector control activities.References
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