Current status of infectious diseases among migrants and non-citizens in Malaysia.

The mass movement of migrants to Malaysia for employment is one of the factors contributing to the emergence and re-emergence of infectious diseases in this country. Despite mandatory health screening for migrants seeking employment, prevalence records of infectious diseases amongst migrant populations in Malaysia are still within negligible proportions. Therefore, the present review highlights the incidence, mortality and overall status of infectious diseases amongst migrants' populations in Malaysia, which maybe be useful for impeding exacerbation of inequalities among them and improving our national health system thru robust and effective emergency responses in controlling the prevalent diseases found among these populations and maybe, Malaysian citizens too. Peer-reviewed articles from January 2016 to December 2020 were searched through online platform including SCOPUS, PubMed, Science Direct, and Google Scholar. Non-peer-reviewed reports and publications from ministry and government websites including data from related agencies were also scoured from in order to ensure that there are no cases being overlooked, as most published articles did not have migrants as the research subjects. A total of 29 studies had been selected in the final analysis. Migrants in Malaysia were at higher risk for tuberculosis, malaria, lymphatic filariasis, cholera, leprosy and leptospirosis. Lymphatic filariasis was still endemic among this population while thousand cases of TB and cholera had been reported among them due to cramp living conditions and poor sanitation in their settlements respectively. While malaria had gradually decreased and become sporadic, the influx of migrant workers had led to the rising of imported malaria cases. Low cases of leprosy had been recorded in Malaysia but a significant proportion of it was contributed by migrant workers. As for leptospirosis, studies found that there are prominent cases among migrant workers, which particularly highest within workers with lower educational attainment. Infectious diseases are still prevalent among migrants in Malaysia due to various interplay factors including their working sectors, country of origin, immunization status, type of settlement, impoverished living conditions, and language and cultural barriers that impeding access to health facilities.

Poverty related diseases amongst Malaysia's low-income community: a review.

Poverty, as proven by several studies, is a driving force behind poor health and hygiene practices. This review attempts to outline common communicable and non-communicable diseases that disproportionately affect Malaysia's 2.91 million low-income households. The current study also looks into the government's housing and healthcare programmes for this demographic to improve their health and well-being. The initial examination yielded incredibly little research on this marginalised community, with event reporting typically generalised to the Malaysian community as a whole rather than analysing disease incidences based on household income, which would better reflect povertydriven diseases. As a result, there is an acute need for more accurate information on the epidemiology of diseases among the poor in order to address this public health issue and provide conclusions that can drive policy designs.

Current status of infectious diseases among migrants and non-citizens in Malaysia

@#The mass movement of migrants to Malaysia for employment is one of the factors contributing to the emergence and re-emergence of infectious diseases in this country. Despite mandatory health screening for migrants seeking employment, prevalence records of infectious diseases amongst migrant populations in Malaysia are still within negligible proportions. Therefore, the present review highlights the incidence, mortality and overall status of infectious diseases amongst migrants’ populations in Malaysia, which maybe be useful for impeding exacerbation of inequalities among them and improving our national health system thru robust and effective emergency responses in controlling the prevalent diseases found among these populations and maybe, Malaysian citizens too. Peer-reviewed articles from January 2016 to December 2020 were searched through online platform including SCOPUS, PubMed, Science Direct, and Google Scholar. Non-peer-reviewed reports and publications from ministry and government websites including data from related agencies were also scoured from in order to ensure that there are no cases being overlooked, as most published articles did not have migrants as the research subjects. A total of 29 studies had been selected in the final analysis. Migrants in Malaysia were at higher risk for tuberculosis, malaria, lymphatic filariasis, cholera, leprosy and leptospirosis. Lymphatic filariasis was still endemic among this population while thousand cases of TB and cholera had been reported among them due to cramp living conditions and poor sanitation in their settlements respectively. While malaria had gradually decreased and become sporadic, the influx of migrant workers had led to the rising of imported malaria cases. Low cases of leprosy had been recorded in Malaysia but a significant proportion of it was contributed by migrant workers. As for leptospirosis, studies found that there are prominent cases among migrant workers, which particularly highest within workers with lower educational attainment. Infectious diseases are still prevalent among migrants in Malaysia due to various interplay factors including their working sectors, country of origin, immunization status, type of settlement, impoverished living conditions, and language and cultural barriers that impeding access to health facilities.

Poverty related diseases amongst Malaysia’s low-income community: a review

@#Poverty, as proven by several studies, is a driving force behind poor health and hygiene practices. This review attempts to outline common communicable and non-communicable diseases that disproportionately affect Malaysia’s 2.91 million low-income households. The current study also looks into the government’s housing and healthcare programmes for this demographic to improve their health and well-being. The initial examination yielded incredibly little research on this marginalised community, with event reporting typically generalised to the Malaysian community as a whole rather than analysing disease incidences based on household income, which would better reflect povertydriven diseases. As a result, there is an acute need for more accurate information on the epidemiology of diseases among the poor in order to address this public health issue and provide conclusions that can drive policy designs.

Molecular characterisation and genetic affinities of Cyclophyllidean cestodes infecting wild rats in Peninsular Malaysia.

Cestode infections is widely reported in rodents, however species identification remains problematic due to the genetic or interspecies variation. Therefore, this study was aimed to verify the Cyclophyllidean parasites recovered from wild rats captured from different forest types using molecular based methods. Maximum-likelihood (ML) and neighbour-joining (NJ) trees were constructed inferred from 18 small subunit nuclear ribosomal RNA gene (18SrDNA) and mitochondrial cytochrome c oxidase subunit one gene (COX1) sequences of cestode worms recovered from 124 individuals from four rat species. Sequences obtained from both Hymenolepis diminuta and Hydatigera parva represents the first records in Malaysia. All the sequences were successfully amplified with product with total length of 205 and 1202 base pairs (bp), respectively. Three cestode species from the Family Hymenolepididae (Hymenolepis diminuta) and Family Taeniidae (Hydatigera parva; Hydatigera taeniaeformis) were successfully characterized using phylogenetic analyses and haplotype networking. Phylogenetic analysis showed that H. diminuta, Hydatigera parva (Hy. parva) and Hydatigera taeniaeformis (Hy. taeniaeformis) formed its own monophyletic clade in 18SrDNA analyses. Results also showed that Hy. taeniaeformis shared the same haplotype group with Hy. taeniaeformis from China (COX1) and linked with Hy. taeniaeformis from Japan (18SrDNA) while the Malaysian H. diminuta clearly formed a separate haplotype and networked with other regions. The Malaysian Hy. parva isolation, on the other hand, appeared to be genetically distinct from the European Hy. parva (Spain) strain, but closely linked to the local isolates. Molecular methods employed successfully improved in the detection of complex species in this group. The findings showed that molecular data can be useful to deeply study intra-specific variation in other cestode worms.

Molecular characterisation and genetic affinities of Cyclophyllidean cestodes infecting wild rats in Peninsular Malaysia

@#Cestode infections is widely reported in rodents, however species identification remains problematic due to the genetic or interspecies variation. Therefore, this study was aimed to verify the Cyclophyllidean parasites recovered from wild rats captured from different forest types using molecular based methods. Maximum-likelihood (ML) and neighbour-joining (NJ) trees were constructed inferred from 18 small subunit nuclear ribosomal RNA gene (18SrDNA) and mitochondrial cytochrome c oxidase subunit one gene (COX1) sequences of cestode worms recovered from 124 individuals from four rat species. Sequences obtained from both Hymenolepis diminuta and Hydatigera parva represents the first records in Malaysia. All the sequences were successfully amplified with product with total length of 205 and 1202 base pairs (bp), respectively. Three cestode species from the Family Hymenolepididae (Hymenolepis diminuta) and Family Taeniidae (Hydatigera parva; Hydatigera taeniaeformis) were successfully characterized using phylogenetic analyses and haplotype networking. Phylogenetic analysis showed that H. diminuta, Hydatigera parva (Hy. parva) and Hydatigera taeniaeformis (Hy. taeniaeformis) formed its own monophyletic clade in 18SrDNA analyses. Results also showed that Hy. taeniaeformis shared the same haplotype group with Hy. taeniaeformis from China (COX1) and linked with Hy. taeniaeformis from Japan (18SrDNA) while the Malaysian H. diminuta clearly formed a separate haplotype and networked with other regions. The Malaysian Hy. parva isolation, on the other hand, appeared to be genetically distinct from the European Hy. parva (Spain) strain, but closely linked to the local isolates. Molecular methods employed successfully improved in the detection of complex species in this group. The findings showed that molecular data can be useful to deeply study intra-specific variation in other cestode worms.

Public health status of Myanmar refugees in South East Asia: A Malaysian case study

@#The United Nations High Commissioner for Refugees (UNHCR) reports over 80 million people are displaced worldwide with approximately 26.3 million categorized as refugees and over a million residing temporarily in South East Asia. Despite the lack of national legislative framework in place for refugees and asylum seekers (RAS), Malaysia hosts approximately 178,140 as registered with UNHCR and the majority originate from Myanmar. In this review, we examine refugees from South East Asia, particularly from Myanmar that have contributed to the largest influx of refugees to this region with a focus on their health status. The present study traces barriers to the health care of refugees in the country of asylum and also the challenges faced by these communities in accessing health services.

Post-era mass drug administration: an update on intestinal parasitic infections in urban poor communities in Peninsular Malaysia.

The health impact of a Malaysian national helminth control program which provided school-based anthelmintic chemotherapy from 1974 to 1983 was re-visited after three decades post MDA and associated risk factors amongst urban poor communities identified. Stool samples collected were screened using the formalin ethyl-acetate concentration technique recovered at least one species of helminth and/or protozoan. Despite a steady decline observed between 1974-1983 however, post MDA infections continue to persist in pockets of communities moderately (18.9%; n=39/206) with higher infection recorded amongst PPR flat residents (22.5%, n=16/71). Among risk factors identified, waste management method was the primary factor for Ascaris lumbricoides infections (n=33; 16.0%), whereas age, education, employment and source of drinking water were significant risk factors for cryptosporidiosis. Despite the government's efforts to improve health through the provision of basic amenities to the general public, higher prevalence values amongst PPR flat dwellers suggests the need to implement targeted chemotherapeutic treatment of, once a year deworming as recommended by World Health Organization when the baseline prevalence of soil-transmitted helminth infections in the community is over 20%, in addition to preventive measures though improvements in health awareness programs and improved waste management methods.

Post-era mass drug administration: an update on intestinal parasitic infections in urban poor communities in Peninsular Malaysia

@#The health impact of a Malaysian national helminth control program which provided school-based anthelmintic chemotherapy from 1974 to 1983 was re-visited after three decades post MDA and associated risk factors amongst urban poor communities identified. Stool samples collected were screened using the formalin ethyl-acetate concentration technique recovered at least one species of helminth and/or protozoan. Despite a steady decline observed between 1974-1983 however, post MDA infections continue to persist in pockets of communities moderately (18.9%; n=39/206) with higher infection recorded amongst PPR flat residents (22.5%, n=16/71). Among risk factors identified, waste management method was the primary factor for Ascaris lumbricoides infections (n=33; 16.0%), whereas age, education, employment and source of drinking water were significant risk factors for cryptosporidiosis. Despite the government’s efforts to improve health through the provision of basic amenities to the general public, higher prevalence values amongst PPR flat dwellers suggests the need to implement targeted chemotherapeutic treatment of, once a year deworming as recommended by World Health Organization when the baseline prevalence of soil-transmitted helminth infections in the community is over 20%, in addition to preventive measures though improvements in health awareness programs and improved waste management methods.

Entamoeba infections and associated risk factors among migrant workers in Peninsular Malaysia

@#The influx of low skilled migrant workers to Malaysia from low socio-economic countries where gastrointestinal parasitic infections are prevalent has raised concerns about transmission to the local population. Three methods for detection (serology, microscopy and molecular techniques) were utilized to identify Entamoeba infections amongst the targeted cohort and determine risk factors associated with infection. Serological screening of 484 migrant workers from five working sectors in Peninsular Malaysia using IgG4 ELISA based on the rPPDK antigen showed an overall seroprevalence of 7.4% (n = 36; CL95 = 5.3–10.1%) with only one factor statistically associated with seropositivity of anti-amoebic antibodies, i.e. years of residence in Malaysia (χ2 1 = 4.007, p = 0.045). Microscopic examination of 388 faecal samples for protozoan cysts and trophozoites showed a slightly higher prevalence (11.6%; n=45; CL95: 8.4–14.8%). Meanwhile, amplification of the 16S rDNA gene detected two species i.e. Entamoeba dispar (23/388; 5.9%; CL95: 3.6–8.3%) and E. histolytica (11/388; 2.8%; CL95: 1.2–4.5%) and mixed infections with both parasites in only three samples (3/388; 0.8%; CL95: 0.2–2.2%). Entamoeba dispar infection was significantly associated with those employed in food and domestic services (χ2 4 = 12.879, p = 0.012). However, none of the factors affected the prevalence of E. histolytica infection. Despite the low prevalence of E. histolytica in faecal samples of the study cohort, the presence of this pathogenic parasite still poses potential public health risks and calls for tighter control strategies based on better availability of chemotherapeutic treatment and accessibility to appropriate health education.

Impact of pH on the viability and morphology of Blastocystis isolates.

Blastocystis sp. is ubiquitous in avian, mammalian and human hosts and propagates in either neutral or slightly alkaline conditions within the host's gastro-intestinal tract. Of the few previous studies on this enteric protozoan parasite in feline and canine hosts, prevalence values have been shown to range between 0 to 70.8%. In view of the close association between humans, and canine and feline hosts as companion animals, faecal samples of 180 Felis catus and 82 Canis lupus, collected from Penang and Kuala Lumpur, Malaysia, were initially screened by in vitro cultivation followed by molecular characterization. No positive isolates were identified in culture but in 12 feline samples DNA barcoding detected a zoonotic subtype Blastocystis ST1 for the first time. Consequently, avian and human isolates, which had previously been successfully cultured, were used to investigate the impact of pH on the viability and morphology of Blastocystis sp. The use of Trypan blue showed that the number of viable cells increased when exposed to pH 4 and a significant increase in viability occurred in pH values of 5 to 7. Development of Blastocystis cells in both isolates was suppressed in media less than pH 5 followed by the disappearance of viable cells from avian isolates in more acidic media below pH 4. Morphologically at pH 4 cells from avian isolates were less rounded, and with wrinkled / shrunken surfaces, than the more normal rounded cells from human isolates. On the other hand, at values below pH 3, no viable cells in human isolates were visible. The present findings therefore confirm that gastro-intestinal pH is an important determinant of Blastocystis viability and consequently influences the epidemiology of infection within avian, mammalian and human hosts.

Genetic diversity of rodent Blastocystis sp. from Peninsular Malaysia.

Rodents are ubiquitous zoonotic vectors for many human pathogens including Blastocystis sp. In this study, we examined the prevalence and subtypes of Blastocystis sp. in rodents captured from Peninsular Malaysia. A total of 293 rodents predominantly brown rat (Rattus norvegicus) (290 of 293, 99.0%) and house shrew (Suncus murinus) (3 of 293, 1.0 %), were captured in the vicinity of popular eateries in two cities (Kuala Lumpur and Ipoh) in Peninsular Malaysia. In vitro cultivation method showed presence of Blastocystis sp. in approximately half (133 of 290, 45.9%) of the brown rats tested. Among the 47 Blastocystis isolates subtyped using partial small subunit ribosomal RNA gene analysis, ST4 was the most abundant (43 of 47, 91.5%) followed by ST1 (2 of 47, 4.3%), ST5 (1 of 47, 2.1%) and ST7 (1 of 47, 2.1%). Our findings highlighted the importance of rodents as a source of Blastocystis sp. infection in Malaysia and showed the high prevalence of ST4 within the rodent population infected with Blastocystis sp.

Current status of Blastocystis in cockroaches.

There are few reports on Blastocystis spp. infections in invertebrate hosts namely, cockroaches. Due to their close proximity to humans especially to their dwellings prompted this study as these organisms could possibly play a role in human transmission. A total of 151 cockroaches consisted predominantly of nymph and adult stages were captured from several types of dwellings in the state of Perak and Selangor, Malaysia. Approximately half (40.4%) of the cockroach intestinal contents screened were positive and were found associated to two main factors, host-stage and types of dwellings. The granular and vacuolated forms were the most common cell form found in the in vitro cultures and were morphologically similar to B. hominis. However, the surface coat observed was thick with an electron lucent area observed in the central vacuole. The isolates grew in room temperature but optimal growth was observed at a 24ºC similar to the reptilian Blastocystis with a high number of cells were recovered. Using the DNA barcoding method, two isolates were identified as ST3 (allele 56), one isolate was consider as the new subtype with close relation to allele 114.

Serological and molecular identification of Leptospira spp. in swine and stray dogs from Malaysia.

Leptospirosis is endemic in Malaysia with Leptospira species extensively isolated from domestic and wild animals. Rats were found to be the principal maintenance hosts followed by cattle, pigs, and dogs. The objectives of this study were to isolate and identify Leptospira serovars circulating among swine from three different farms and also from stray dogs and cats from Klang valley, Selangor, Malaysia. Urine and kidney samples collected from 150 stray dogs, 50 cats and 81 swine were inoculated into semi-solid Ellinghausen McCullough Johnson and Harris (EMJH) media supplemented with additional 5-Fluorouracil. Dark field microscopy revealed only one positive culture of Leptospira from dog and swine samples, but all cat samples were negative. The PCR technique using published primers detected 11 positives in urine samples of dogs and 5 positives from swine. The microscopic agglutination test (MAT) confirmed the presence of two serovars in both dog and swine populations namely, L. interrogans serovar Canicola and L. interrogans serovar Pomona (MAT > 100), with Not I-PFGE analyses separating these two serovars into distinct profiles. Despite the low prevalence in stray dogs, the latter may play an important role in the contamination of the environment. Swine can also pose a potential risk of infection to humans and other domestic animals, especially those living close to swine farms. Thus improving hygiene and eradication of rodents in swine farms are likely to reduce the risk of infection.

Morphological and molecular detection of Blastocystis in wildlife from Tioman Island, Malaysia.

Blastocystis infection is widely reported in wildlife, livestocks and in non-human primates however, occurrence in Malaysian wildlife is scarce. A wildlife survey on Tioman Island captured six water monitor lizard (Varanus salvator), four mouse-deer (Tragulus sp.) and one Malayan porcupine (Hystrix brachyura) based on convenience sampling. Intestinal contents from each animal were subjected to in vitro cultivation method using Jones medium supplemented with 10% horse serum. Low prevalence of infections was detected with only 1/6 (16.7%) water monitor lizard and 1/4 (25%) mouse-deer infected. The vacuolated form was the most common cell form found in both cultures with similar morphology to B. hominis. However, the monitor lizard isolate propagated well in the laboratory for several months using Jones medium while mouse-deer isolate could not be maintained for more than a week. The reptilian isolates grew optimally at a lower temperature of 24ºC compared to 37ºC for the mouse-deer isolate. Using the DNA barcoding method, both isolates were confirmed to be Blastocystis sp. Sequence obtained from a monitor lizard isolate has 94% sequence identity to B. lapemi, an isolate recovered from a reptile sea-snake whereas a mouse-deer isolate has 99% sequence identitical to B. hominis HJ01-7. The phylogenetic tree revealed that the monitor lizard isolate were positioned within the herptiles clade (clade VIII) while the mouse deer isolate located at the homoithermal clade (clade IV). The present paper is the first report on the presence as well as genetic characteristics of Blastocystis in wildlife captured from Tioman Island, Pahang.

Morphological and molecular detection of Blastocystis in wildlife from Tioman Island, Malaysia

Blastocystis infection is widely reported in wildlife, livestocks and in non-human primates however, occurrence in Malaysian wildlife is scarce

Isolation and Identification of an Emerging Pathogen, Kocuria marina, from Rattus rattus diardii.

Members of the genus Kocuria are commonly found in the environment and they are also commensals of the mammalian skin and oropharynx mucosa. Human infections, although rare, are increasingly being reported recently suggesting that this genus has mostly been overlooked or misidentified. Its transmission route however, is still not known. We report here the isolation and identification of a Kocuria marina isolate from the lung of a wild urban rat (Rattus rattus diardii) caught at a wet market. The isolate was susceptible to most of the commonly used antibiotics. The finding suggests a possibility that rats could be a vector for K. marina.

Stray animal and human defecation as sources of soil-transmitted helminth eggs in playgrounds of Peninsular Malaysia.

Soil contaminated with helminth eggs and protozoan cysts is a potential source of infection and poses a threat to the public, especially to young children frequenting playgrounds. The present study determines the levels of infection of helminth eggs in soil samples from urban and suburban playgrounds in five states in Peninsular Malaysia and identifies one source of contamination via faecal screening from stray animals. Three hundred soil samples from 60 playgrounds in five states in Peninsular Malaysia were screened using the centrifugal flotation technique to identify and determine egg/cyst counts per gram (EPG) for each parasite. All playgrounds, especially those in Penang, were found to be contaminated with eggs from four nematode genera, with Toxocara eggs (95.7%) the highest, followed by Ascaris (93.3%), Ancylostoma (88.3%) and Trichuris (77.0%). In addition, faeces from animal shelters were found to contain both helminth eggs and protozoan cysts, with overall infection rates being 54% and 57% for feline and canine samples, respectively. The most frequently occurring parasite in feline samples was Toxocara cati (37%; EPG, 42.47 ± 156.08), while in dog faeces it was Ancylostoma sp. (54%; EPG, 197.16 ± 383.28). Infection levels also tended to be influenced by season, type of park/playground and the texture of soil/faeces. The occurrence of Toxocara, Ancylostoma and Trichuris eggs in soil samples highlights the risk of transmission to the human population, especially children, while the presence of Ascaris eggs suggests a human source of contamination and raises the issue of hygiene standards and public health risks at sites under investigation.

Comparison between Quantitative Buffy Coat (QBC) and Giemsa-stained Thin Film (GTF) technique for blood protozoan infections in wild rats.

The quantitative buffy coat (QBC) technique and conventional Giemsa thin blood smear was compared to determine the sensitivity and specificity of the technique in detecting blood parasitic infection of the rodent populations from four urban cities in Peninsular Malaysia. A total of 432 blood samples from four rat species (Rattus norvegicus, Rattus rattus diardii, Rattus exulans and Rattus argentiventer) were screened using both techniques and successfully detected two blood protozoan species (Trypanosoma lewisi and Plasmodium sp.) with Trypanosoma lewisi predominantly infecting the population. Results showed that Giemsa-stained thin film (GTF) was the better detection method on blood parasitemia (46.7%) compared to Quantitative Buffy Coat method (38.9%) with overall detection technique sensitivity and specificity at 83.2% and 74.8% respectively. The sensitivity in detection of Trypanosoma lewisi was 84.4% with value slightly lower for Plasmodium sp. infections at 76.6%. Statistical analysis proved that GTF technique was significantly more sensitive in the detection of blood protozoan infections in the rodent population compared to QBC (p<0.05).

Epidemiology of blood parasitic infections in the urban rat population in peninsular Malaysia.

A total of 719 wild rats were captured from four localities representing the west (Kuala Lumpur), east (Kuantan), north (Georgetown) and south (Malacca) to determine the diversity of blood protozoan from the urban wild rat population in peninsular Malaysia. Five rat species were recovered with Rattus rattus diardii being the most dominant species, followed by Rattus norvegicus, Rattus exulans, Rattus annandalei and Rattus argentiventer. Two blood protozoan species were found infecting the rodent population namely, Plasmodium sp. (42.1%) and Trypanosoma lewisi (25.0%). This study reports the presence of Plasmodium sp. for the first time in the rodent population in Malaysia. Two main intrinsic factors were identified affecting the parasitic infections. Trypanosoma lewisi infections were influenced by host age and sex with infections observed higher in male and juvenile rats meanwhile Plasmodium sp. infections were observed almost similar in both sexes. However, infections were higher in sub-adult rats.