An Update on the Epidemiological Features of Imported Schistosomiasis and Cystic Echinococcosis in Kuwait, 2010-2018.

OBJECTIVE: Kuwait is considered a non-endemic country for most parasitic infections. However, ∼70% of 4.7 million residents in Kuwait are expatriates from Asian and African countries, which are endemic for parasitic infections. Results of microbiological investigations for schistosomiasis and cystic echinococcosis (CE) performed in a reference national laboratory were retrospectively collected and analyzed to provide an insight on the epidemiology of these 2 neglected tropical diseases in Kuwait. SUBJECTS AND METHODS: Schistosoma infection in fecal and urine specimens from suspected patients was detected by microscopy. Schistosoma and CE infections were also detected by indirect hemagglutination assays (IHAs) using blood specimens. Patients' epidemiological data were extracted from the laboratory records. RESULTS: The overall prevalence rates of schistosomiasis and CE were 19.0 and 5.8%, respectively. Almost all schistosomiasis cases were seen among Egyptians, especially among males, and a significantly higher prevalence (p < 0.05) was seen for CE cases among the Syrian residents. A decreasing annual trend was observed for both the parasitic infections over time in Kuwait. CONCLUSIONS: This study confirmed that schistosomiasis is not autochthonous in Kuwait, as all cases were detected among expatriates from Schistosoma-endemic countries. Our data also showed that CE remains endemic among humans and livestock in Kuwait as is also seen in other Middle Eastern countries.

Cysticercosis, a Potential Public Health Concern in Kuwait: A New Diagnostic Method to Screen Taenia solium Taeniasis Carriers in the Expatriate Population.

OBJECTIVE: Taenia solium infection is not endemic to Kuwait, butseveral casesof cysticercosis have been detected in Kuwaiti nationals with no history of travelling to endemic countries. Infected domestic helpers/food handlers from endemic countries who may have escaped detection of infection by microscopy at the time of their arrival in Kuwait have been suspected as the possible source of infection. This study determined the seroprevalence of T. solium among domestic helpers/food handlers by screening their blood using a sensitive taeniasis-specific anti-rES33 antibody assay. SUBJECTS AND METHODS: Newly arrived domestic helpers (n = 500) and food handlers (n = 500) from endemic countries were enrolled in the period 2015-2017. T. solium-specific rES33 antigen was expressed and purified from human embryonic kidney (HEK)293-6E cells using the pTT5 mammalian expression vector. Stool samples were processed for microscopy, and blood samples were screened to detect anti-T. soliumtaeniasis-specific IgG antibodies by ELISA. RESULTS: All stool samples were negative for T. soliumparasiteeggs by microscopy. However, 42 individuals (4.2%) tested positive for T. soliumtaeniasis-specific IgG antibodies. Though statistically not significant, the IgG seropositivity was higher in individuals with a lower education level, a low-income background, and a lower frequency of hand-washing. CONCLUSIONS: This is the first report from Kuwait and the Middle East on the detection of anti-T. soliumtaeniasis-specific serum IgG antibodies among the high-risk expatriate population. The results emphasize the importance of efficient and sensitive screening of T. solium carriers and thus the prevention of infection transmission and development of cysticercosis in the local population.

TGF-ß1 levels and intraocular tissue alterations in mice infected with a virulent type I RH Toxoplasma gondii strain.

Toxoplasmosis is generally self-limiting in healthy adults but it may cause toxoplasmic retinochoroiditis in cases of congenital infection leading to blindness. The importance of host genetics in determining disease severity in ocular toxoplasmosis has been shown in different inbred mouse strains using low-virulence toxoplasma strain. In this study, we studied intraocular immune response and tissue alterations in the genetically resistant BALB/c and susceptible MF1 mice infected with a virulent type I RH Toxoplasma gondii strain by intravitreal route. We observed a significant up-regulation of IFN-γ and TNF-α to >2200 pg/ml and >300 pg/ml respectively in the blood of both BALB/c and MF1mice during the early stages of post intraocular infection (p < 0.01) but the levels dropped sharply to normal during the late stages of the infection on day 26. The cytokine levels detected were higher in the MF1 mice compared with the BALB/c mice and a relatively higher levels were observed in the aqueous humour (AqH) than in the blood of both group of mice. The TGF-ß1 level in the blood and AqH of BALB/c mice remained low throughout the infection period compared with MF1 mice which showed gradual increase to 50 pg/ml in the blood and AqH during the early stages of infection which then further increased 2-fold-132 pg/ml on day 11 (p < 0.01) and remained high till the last day of observation on day 26 except that the TGF-ß1 level in AqH dropped sharply to normal level. In summary, our results support that TGF-ß1 may down-regulate the effector functions of anti-Toxoplasma cellular immunity during acute toxoplasmosis. We document that a mild Th1 pro-inflammatory response in the BALB/c mice with high IFN-γ and TNF-α and, low TGF-ß1 levels during the early stages of infection may have contributed to an effective cellular immune response leading to lower morbidity, mortality and less ocular tissue damage. However in the MF1 mice, a significantly high TGF-ß1 level in the blood as well as in the AqH during the acute intra-ocular toxoplasma infection may have adversely interfered with an effective cellular immune response leading to an increased mortality and extensive ocular tissue damage with parasite tachyzoites observed in the pigment epithelium layers.

Seroprevalence of toxocariasis among allergic patients in Kuwait and its association with eosinophilia.

Toxocariasis is a worldwide helminthic infection which is transmitted from infected dogs and cats and has been associated with peripheral blood eosinophilia. The Centers for Disease Control and Prevention (CDC) placed toxocariasis among the top 6 parasitic diseases in the USA which are prioritized for public health action. To our knowledge, there are no reports on human toxocariasis in Kuwait or in the other Gulf Cooperation Council (GCC) countries. This study aims at investigating the seroprevalence of toxocariasis among allergic patients in Kuwait and its association with eosinophilia, age, gender, nationality, and history of direct contact with dogs or cats. From September to December 2021, the laboratory records of allergic patients referred to Al-Rashed Allergy Hospital, Kuwait were reviewed and a total of 400 serum samples were selected: 200 samples from patients with normal eosinophil count (< 500 cells/µl) and 200 samples from patients with eosinophilia (> 500 cells/µl). The sera were screened for anti-Toxocara canis IgG antibodies via antibody enzyme-linked immunosorbent assay (Ab-ELISA). The seropositive patients were asked about their history of direct contact with dogs or cats. Statistical analyses were performed using Microsoft Excel® Analysis ToolPak software. Toxocariasis seropositivity was detected in 10 out of 400 (2.5%) allergic patients. Five patients had eosinophilia while 5 had normal eosinophil count. There was no difference in mean age or gender between Toxocara-seropositive and seronegative patients (p > 0.05). The seroprevalence rate was lower-than-expected among Kuwaiti patients (2/307, 0.7%) in comparison with non-Kuwaiti patients (8/57, 14.0%) (χ2 = 33.603, df = 1, p < 0.001) who originated from endemic South/Southeast Asian countries. Seven out of 8 (87.5%) seropositive patients had a history of direct contact with cats, dogs, or both. The seroprevalence rate of toxocariasis among allergic patients in Kuwait was 2.5%. Raising awareness and early deworming treatment/prophylaxis for juvenile dogs and cats remain crucial for toxocariasis prevention.

Current Status and the Epidemiology of Malaria in the Middle East Region and Beyond.

Vector-borne parasitic infectious diseases are important causes of morbidity and mortality globally. Malaria is one of the most common vector-borne parasitic infection and is caused by five Plasmodium species, namely P. falciparum, P. vivax, P. ovale, P. malariae, and P. knowlesi. Epidemiologically, differences in the patterns of malaria cases, causative agent, disease severity, antimicrobial resistance, and mortality exist across diverse geographical regions. The world witnessed 229 million malaria cases which resulted in 409,000 deaths in 2019 alone. Although malaria cases are reported from 87 countries globally, Africa bears the brunt of these infections and deaths as nearly 94% of total malaria cases and deaths occur in this continent, particularly in sub-Saharan Africa. Most of the Middle East Region countries are malaria-free as no indigenous cases of infection have been described in recent years. However, imported cases of malaria continue to occur as some of these countries. Indeed, the six Gulf Cooperation Council (GCC) countries have large expatriate population originating from malaria endemic countries. In this review, the current status and epidemiology of malaria in the Middle East Region countries and other malaria-endemic countries that are home to a large migrant workforce being employed in Middle East Region countries are discussed.

Current Epidemiological Characteristics of Imported Malaria, Vector Control Status and Malaria Elimination Prospects in the Gulf Cooperation Council (GCC) Countries.

Malaria is the most common vector-borne parasitic infection causing significant human morbidity and mortality in nearly 90 tropical/sub-tropical countries worldwide. Significant differences exist in the incidence of malaria cases, dominant Plasmodium species, drug-resistant strains and mortality rates in different countries. Six Gulf Cooperation Council (GCC) countries (Bahrain, Kuwait, Qatar, Oman, Saudi Arabia and United Arab Emirates, UAE) in the Middle East region with similar climates, population demographics and economic prosperity are aiming to achieve malaria elimination. In this narrative review, all studies indexed in PubMed describing epidemiological characteristics of indigenous and imported malaria cases, vector control status and how malaria infections can be controlled to achieve malaria elimination in GCC countries were reviewed and discussed. These studies have shown that indigenous malaria cases are absent in Bahrain, Kuwait, Qatar and UAE and have progressively declined in Oman and Saudi Arabia. However, imported malaria cases continue to occur as GCC countries have large expatriate populations originating from malaria-endemic countries. Various malaria control and prevention strategies adopted by GCC countries including more stringent measures to reduce the likelihood of importing malaria cases by prior screening of newly arriving expatriates and vector elimination programs are likely to lead to malaria elimination in this region.

A Large Case Series of Neurocysticercosis in Kuwait, a Nonendemic Arabian Gulf Country in the Middle East Region.

Neurocysticercosis (NCC), a leading global cause of severe progressive headache and epilepsy, in developed or affluent countries is mostly diagnosed among immigrants from poor or developing Taenia solium taeniasis-endemic countries. Taeniasis carriers in Kuwait are routinely screened by insensitive stool microscopy. In this study, enzyme-linked immunoelectrotransfer blot (EITB) was used as a confirmatory test for NCC. Screening was performed on 970 patients referred for suspected NCC on the basis of relevant history and/or ring-enhancing lesions on computed tomography and/or magnetic resonance imaging during a 14-year period in Kuwait. Demographic data and clinical details were retrieved from laboratory or hospital records. EITB was positive in 150 subjects (15.5%), including 98 expatriates mostly originating from taeniasis-endemic countries and, surprisingly, 52 Kuwaiti nationals. The clinical details of 48 of 50 NCC cases diagnosed during 2014-2019 were available. Most common symptoms included seizures, persistent headache with/without fever, and fits or loss of consciousness. Cysticercal lesions were located at various brain regions in 39 of 48 patients. Multiple members of 3 families with NCC were identified; infection was linked to domestic workers from taeniasis-endemic countries and confirmed in at least 1 family. Our data show that NCC is predominantly imported in Kuwait by expatriates originating from taeniasis-endemic countries who transmit the infection to Kuwaiti citizens.

Decreasing trend of imported malaria cases but increasing influx of mixed P. falciparum and P. vivax infections in malaria-free Kuwait.

Malaria still continues to be the most important parasitic disease worldwide, affecting 228 million people and causing 405,000 deaths each year. In this retrospective study during 2013 to 2018, we documented the incidence of imported malaria infection and evaluated the impact of malaria preventive measures in Kuwait, a non-endemic country. The epidemiologic and demographic data of all malaria cases was collected from the Infectious Diseases Hospital, Kuwait where all suspected cases of malaria are referred for confirmation and therapeutic intervention. The diagnosis of malaria infection was done by microscopy of Giemsa stained blood films. Selected samples were retested with BinaxNOW® Malaria rapid test and molecular assay to reconfirm the Plasmodium spp. or mixed infection. Overall, 1913 (25.9%) malaria cases were detected, 81.5% of which were among male subjects. Male subjects had higher incidence of P. vivax malaria (113; 91.1%) and mixed infection with P. falciparum and P. vivax (1245; 90.0%) compared to females who had higher rate of P. falciparum infection (52.4%). An overwhelming majority of malaria cases (1895; 99.1%) were detected among expatriates from malaria-endemic countries; India (1012; 52.9%), Pakistan (390; 20.4%), Afghanistan (94; 4.9%) and African countries (313; 16.3%). Only 18 cases involved Kuwaiti nationals, all with a history of travel to African countries. The majority of malaria cases were detected during the summer and fall months (May-October). Our data showed that the incidence rate of imported malaria cases was stable during 2013 to 2018, however, the incidence of total malaria cases showed a declining trend over the years. This study confirms that the preventive program has been successful in reducing the incidence of imported malaria infections in Kuwait. The most striking finding of this study was high incidence of mixed infection with P. falciparum and P. vivax, with almost all (97%) cases among workers from India.