Giardiasis among different tribes of Orang Asli in Malaysia: Highlighting the presence of other family members infected with Giardia intestinalis as a main risk factor

The flagellate protozoan parasite, Giardia intestinalis, is widely distributed throughout the world with a high prevalence in developing countries in the tropics and subtropics, including Malaysia. Approximately 200 million people are infected with the parasite globally, with 500,000 new cases reported annually. This cross-sectional study was conducted among three tribes of Orang Asli communities in Selangor, Perak and Pahang states of Malaysia. The main objective was to determine the prevalence of and risk factors for giardiasis. Stool samples were collected from 500 individuals aged between 2 and 74years (males=219, females=281). The samples were examined with formalin-ether sedimentation and trichrome staining techniques. Socioeconomic data were collected through a pre-tested questionnaire. The overall prevalence of giardiasis was 20.0% with the highest prevalence in the Proto-Malays (33.3%) followed by Negritos (20.1%) and Senois (10.4%). The positive cases showed a decrease with increasing age and most of the positive cases were observed in individuals less than 24years old. Males had significantly higher prevalence than females (χ(2)=5.283, P=0.022). Logistic regression analysis of the overall population studied and the Senoi tribe confirmed that being a child aged less than 15years, being male, the consumption of raw vegetables and the presence of other family members infected with G. intestinalis were the main risk factors for giardiasis. The presence of other family members infected with G. intestinalis was the only risk factor highlighted in the Proto-Malay and Negrito tribes. Diarrhoea was significantly associated with giardiasis. However, the cause and effect relationship has yet to be determined. Thus, screening family members and treating the infected individuals are the main strategies that should be adopted by the public health authority in combating this infection in Orang Asli communities as well as health education regarding good personal and food hygiene practises.     

Fatty acid preference of mycelium-bound lipase from a locally isolated strain of <Emphasis Type="Italic">Geotrichum candidum</Emphasis>

Mycelium-bound lipase (MBL) was prepared using a strain of Geotrichum candidum isolated from local soil. At the time of maximum lipase activity (54 h), the mycelia to which the lipase was bound were harvested by filtration and centrifugation. Dry MBL was prepared by lyophilizing the mycelia obtained. The yield of MBL was 3.66 g/l with a protein content of 44.11 mg/g. The lipase activity and specific lipase activity were 22.59 and 510 U/g protein, respectively. The moisture content of the MBL was 3.85%. The activity of free (extracellular) lipase in the culture supernatant (after removal of mycelia) was less than 0.2 U/ml. The MBL showed selectivity for oleic acid over palmitic acid during hydrolysis of palm olein, indicating that the lipase from G. candidum displayed high substrate selectivity for unsaturated fatty acid containing a cis-9 double bond, even in crude form. This unique specificity of MBL could be a direct, simple and inexpensive way in the fats and oil industry for the selective hydrolysis or transesterification of cis-9 fatty acid residues in natural triacylglycerols.     

In-situ crosslinking of Aspergillus flavus lipase: Improvement of activity, stability and properties

Summary The mycelium-bound lipase of Aspergillus flavus was stabilised by cross-linkage using glutaraldehyde or methylglyoxal. Lipase activity was enhanced by up to 48% by treatment with methylglyoxal but not by glutaraldehyde. Cross-linking with methylglyoxal increased the thermal stability of the lipase by 58% at 50 °C     

Levels of Metallic Elements and Their Potential Relationships to Cognitive Function among Elderly from Federal Land Development Authority (FELDA) Settlement in Selangor Malaysia

Exposure to toxic metals and excessive amount of trace elements is a risk factor of cognitive decline. Continuous monitoring of these elements by the use of metabolically inactive tissues such as fingernails may help in taking preventive measures to delay the cognitive decline process. In this study, the cognitive function of 54 elderlies (60–72 years old) from FELDA Sungai Tengi, Selangor, was evaluated using the Malay version of Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA). The levels of arsenic (As), cadmium (Cd), copper (Cu), manganese (Mn), lead (Pb), and zinc (Zn) in fingernail were detected using Inductively Coupled Plasma-Mass Spectrometry. Results showed that (92.6 %) our population was cognitively impaired based on the MoCA with mean score of 18.07?±?5.11. The mean level of elements in fingernails for As, Cd, Cu, Mn, Pb, and Zn were 16.68?±?3.52, 4.26?±?0.91, 4.81?±?1.16, 1.00?±?0.23, 1.83?±?0.47, and 40.86?±?10.81 μg/g, respectively. Significant inverse correlations were observed between MoCA with age (r?=??0.543, p?<?0.01), Cu level (r?=??0.330, p?<?0.05), and Mn level (r?=??0.496, p?<?0.01). MMSE was correlated to age (r?=??0.346, p?<?0.05) only. In conclusion, besides aging, the progression of cognitive decline among the elderly FELDA population was associated with increased levels of copper and manganese.     

Relationship between γ‐interferon gene polymorphisms and susceptibility to brucellosis infection

Interferon‐gamma (IFN‐γ) is a pro‐inflammatory cytokine that plays a pivotal role in the defense mechanism against Brucella infection. It was hypothesized that the IFN‐γ in (+874 A/T in intron 1) TT and +5644 T/A, TT genotypes, which are reportedly associated with high IFN production, are associated with susceptibility to brucellosis in Iranian subjects. Genotyping of these IFN‐γ variants by an allele‐specific polymerase chain reaction method was performed in 281 subjects, comprising 153 patients with active brucellosis and 128 healthy controls. It was found that the +874 minor allele (A) and homozygote genotype (AA) were significantly more frequently present in brucellosis patients than in controls (OR = 2.588; 95% CI, 1.313–5.104; P = 0.006 for the AA genotype; OR = 1.575; 95% CI, 1.124–2.216; P = 0.010 for the A allele). However, the allelic and genotypic distribution of the IFN‐γ polymorphism at position UTR5644 A>T did not differ significantly between patients and controls (P > 0.05). The distribution of haplotypes in this study suggests that the T/A haplotype (+874/UTR5644), which was present more frequently in controls than in patients, may protect subjects against Brucella infection. It is suggested that IFN‐γ +874 AA genotype and A allele are risk factors for developing brucellosis infection in Iranian subjects.     

Lipid and fatty acid variations in muscle tissues of the ‘yellow’ stage of the European eel (Anguilla anguilla) during short-term adaptation to freshwater and seawater under food deprivation

Changes in body mass and water content (WC), lipids, and fatty acid (FA) composition of muscle were determined in European eels (Anguilla anguilla) in the ‘yellow’ stage (sexually immature). The animals were held in either freshwater (FW) or seawater (SW) and deprived of food for four weeks. During this period, body mass decreased steadily. This decrease was accompanied by reduced muscle WC and total lipid in both SW and FW. ‘Yellow’ eels appeared to use lipids in muscle to provide metabolic and osmoregulatory energy. However, they maintained relative constancy in the FA profiles, so that total FA, saturated, monounsaturated, and polyunsaturated FA, were similar between salinities during short-term starvation.     

Flow and sediment transport in vegetated waterways: a review

One of the most important waterway components is vegetation, which play a pivotal role in the flow and sediment transport. Vegetation environment and characteristics, including vegetation porosity or density, shape, flexibility and vegetation height, are significantly affected in vegetated channels. Various vegetation positions and arrangements such as patches significantly affect the sediment deposition rate and flow turbulence. This paper reviews recent works conducted on vegetated open channels, which include the effect of different vegetation arrangements and vegetation characteristics on mass transport and turbulence structure. Studies based on laboratory, field works, and modeling, have been reviewed based on previous methods used by different researchers. Methods used in vegetation porosity evaluation, rate of flow and sediment transport properties are presented. In short, flow and transport depend on the vegetation properties and flow structure conditions.     

Wolbachia strain wAlbB maintains high density and dengue inhibition following introduction into a field population of Aedes aegypti

Aedes aegypti mosquitoes carrying the wAlbB Wolbachia strain show a reduced capacity to transmit dengue virus. wAlbB has been introduced into wild Ae. aegypti populations in several field sites in Kuala Lumpur, Malaysia, where it has persisted at high frequency for more than 2 years and significantly reduced dengue incidence. Although these encouraging results indicate that wAlbB releases can be an effective dengue control strategy, the long-term success depends on wAlbB maintaining high population frequencies and virus transmission inhibition, and both could be compromised by Wolbachia–host coevolution in the field. Here, wAlbB-carrying Ae. aegypti collected from the field 20 months after the cessation of releases showed no reduction in Wolbachia density or tissue distribution changes compared to a wAlbB laboratory colony. The wAlbB strain continued to induce complete unidirectional cytoplasmic incompatibility, showed perfect maternal transmission under laboratory conditions, and retained its capacity to inhibit dengue. Additionally, a field-collected wAlbB line was challenged with Malaysian dengue patient blood, and showed significant blocking of virus dissemination to the salivary glands. These results indicate that wAlbB continues to inhibit currently circulating strains of dengue in field populations of Ae. aegypti, and provides additional support for the continued scale-up of Wolbachia wAlbB releases for dengue control.This article is part of the theme issue ‘Novel control strategies for mosquito-borne diseases’.