Displaying publications 1 - 20 of 76 in total

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  1. Sejdini A, Mahmud R, Lim YA, Mahdy M, Sejdini F, Gjoni V, et al.
    Ann Trop Med Parasitol, 2011 Apr;105(3):241-50.
    PMID: 21801503 DOI: 10.1179/136485911X12987676649584
    Although intestinal parasitic infections (IPI) among children remain a global issue, the current information on such infections in Albanian children is very limited. A cross-sectional study of the IPI in 321 children living in the Albanian counties of Tirana (152) and Elbasan (169) was therefore conducted in 2008, with a pre-tested standard questionnaire employed to gather the relevant personal and clinical data. Using formalin-ether concentration and permanent stains, stool samples were examined microscopically for the ova, cysts and oocysts of any parasites. The overall prevalence of IPI was 19% (61 of 321), with protozoan infections (11·5%) apparently more common than infections with soil-transmitted helminths (STH; 8·1%). Giardia duodenalis was the parasite most frequently detected (10·9%), followed by hookworm (5·6%), Ascaris lumbricoides (1·9%), Trichuris trichiura (0·6%), Cryptosporidium (0·3%) and Entamoeba histolytica/dispar (0·3%). The results of a univariate analysis indicated that the children from Tirana county were significantly more likely to be found infected with STH compared with the children from Elbasan county (12·5% v. 4·1%; P=0·006). Children sampled in the community were also more likely to be found STH-positive than the children sampled as they attended hospitals and health clinics (10·5% v. 6·0%) but this difference did not reach statistical significance. The children found STH-positive were five times more likely to be suffering from diarrhoea than the other children checked in clinical settings (P=0·004) and were also more likely to be suffering from abdominal pain (P=0·054) and/or diminished appetite (P=0·016).
  2. Al-Mekhlafi AM, Al-Mekhlafi HM, Mahdy MA, Azazy AA, Fong MY
    Ann Trop Med Parasitol, 2011 Apr;105(3):187-95.
    PMID: 21801497 DOI: 10.1179/136485911X12987676649421
    Between June 2008 and March 2009, a cross-sectional study of human malaria was carried out in four governorates of Yemen, two (Taiz and Hodiedah) representing the country's highlands and the others (Dhamar and Raymah) the country's coastal plains/foothills. The main aims were to determine the prevalences of Plasmodium infection among 455 febrile patients presenting for care at participating health facilities and to investigate the potential risk factors for such infection. Malarial infection was detected in 78 (17·1%) of the investigated patients and was more likely to be detected among the febrile patients from the highlands than among those presenting in the coastal plains/foothills (22·6% v.13·9%; χ(2)=10·102; P=0·018). Binary logistic-regression models identified low household income [odds ratio (OR)=13·52; 95% confidence interval (CI)=2·62-69·67; P=0·002], living in a household with access to a water pump (OR=4·18; CI=1·60-10·96; P=0·004) and living in a household near a stream (OR=4·43; CI=1·35-14·56; P=0·014) as significant risk factors for malarial infection in the highlands. Low household income was the only significant risk factor identified for such infection in the coastal plains and foothills (OR = 8·20; CI=1·80-37·45; P=0·007). It is unclear why febrile patients in the highlands of Yemen are much more likely to be found to have malarial infection than their counterparts from the coastal plains and foothills. Although it is possible that malarial transmission is relatively intense in the highlands, it seems more likely that, compared with those who live at lower altitudes, those who live in the highlands are less immune to malaria, and therefore more likely to develop febrile illness following malarial infection. Whatever the cause of the symptomatic malarial infection commonly found in the highlands of Yemen, it is a matter of serious concern that should be addressed in the national strategy to control malaria.
  3. Al-Mekhlafi HM, Mahdy MA, 'Azlin MY, Fatmah MS, Norhayati M
    Ann Trop Med Parasitol, 2011 Mar;105(2):135-43.
    PMID: 21396250 DOI: 10.1179/136485911X12899838683368
    Cryptosporidium is a coccidian parasite that is prevalent worldwide, some species of which cause morbidity in both immunocompromised and immunocompetent individuals. The prevalence and predictors of Cryptosporidium infection, and its effect on nutritional status, have recently been explored among 276 children (141 boys and 135 girls, aged 2-15 years) in aboriginal (Orang Asli) villages in the Malaysian state of Selangor. Faecal smears were examined by the modified Ziehl-Neelsen staining technique while socio-economic data were collected using a standardized questionnaire. Nutritional status was assessed by anthropometric measurements. Cryptosporidium infection, which was detected in 7.2% of the aboriginal children, was found to be significantly associated with low birthweight (≤2.5 kg), being part of a large household (with more than seven members) and prolonged breast feeding (>2 years). The output of a binary logistic regression confirmed that large household size was a significant predictor of Cryptosporidium infection (giving an odds ratio of 2.15, with a 95% confidence interval of 1.25-5.02). Cryptosporidium infection is clearly a public-health problem among the aboriginal children of Selangor, with person-to-person the most likely mode of transmission.
  4. Norhaida A, Suharni M, Liza Sharmini AT, Tuda J, Rahmah N
    Ann Trop Med Parasitol, 2008 Mar;102(2):151-60.
    PMID: 18318937 DOI: 10.1179/136485908X252250
    Currently, the laboratory diagnosis of toxocariasis, caused by Toxocara canis or T. cati, mainly relies on serological tests. Unfortunately, however, the specificities of most of the commercial tests that are available for the serodiagnosis of this disease are not very high and this may cause problems, especially in tropical countries where co-infections with other helminths are common. In an effort to develop a serological assay with improved specificity for the detection of Toxocara infection, an IgG(4)-ELISA based on a recombinant version (rTES-30USM) of the 30-kDa Toxocara excretory-secretory antigen (TES-30) has recently been developed. To produce the antigen, the TES-30 gene was cloned via assembly PCR, subcloned into a His-tagged prokaryotic expression vector, and purified by affinity chromatography using Ni(2+)-nitrilotriacetic-acid (Ni-NTA) resin. The performance of the ELISA based on the recombinant antigen was then compared with that of commercial kit, based on an IgG-ELISA, for the serodiagnosis of toxocariasis (Toxocara IgG-ELISA; Cypress Diagnostics, Langdorp, Belgium). Both assays were used to test 338 serum samples, including 26 samples from probable cases of toxocariasis. Assuming that all the probable cases were true cases, the assay based on rTES-30USM demonstrated a sensitivity of 92.3% (24/26) and a specificity of 89.6% (103/115) whereas the commercial kit exhibited a sensitivity of 100% (26/26) but a specificity of only 55.7% (64/115). The high sensitivity and specificity exhibited by the new IgG(4)-ELISA should make the assay a good choice for use in tropical countries and any other area where potentially cross-reactive helminthic infections are common.
  5. Shahid SK
    Ann Trop Med Parasitol, 2008 Jan;102(1):63-71.
    PMID: 18186979 DOI: 10.1179/136485908X252151
    Multidrug-resistant organisms cause late-onset ventilator-associated pneumonia (VAP). In a pilot, randomized and controlled study, the efficacy and safety of cefepime, in late-onset VAP in infants, have now been evaluated in Malaysia. Thirty children aged <1 year with late-onset VAP (i.e. VAP occurring 5 or more days after intubation) were randomized to receive cefepime or, as a control, ceftazidime. The clinical responses and the microbiological clearance of tracheal aspirates were evaluated in each arm. Adverse events, if any, were monitored clinically and by blood tests. Ten of the 15 children given cefepime and five of the 15 given ceftazidime showed a satisfactory clinical response (P<0.1). Cefepime appeared significantly better at clearing polymicrobial infections from tracheal aspirates. There were no fatalities in the cefepime arm but three in ceftazidime (P<0.1). The mean (S.E.) durations of antibiotic use were 9.4 (1.5) days for cefepime and 7.6 (1.0) days for ceftazidime (P>0.05). No serious adverse effects were observed in either arm. In conclusion, in late-onset VAP in infants, cefepime monotherapy appears to be at least as effective and safe as ceftazidime monotherapy, with better microbiological clearance.
  6. Norhayati M, Al-Mekhlafi HM, Azlin M, Nor Aini U, Shaik A, Sa'iah A, et al.
    Ann Trop Med Parasitol, 2007 Sep;101(6):547-50.
    PMID: 17716439
  7. Kirton LG
    Ann Trop Med Parasitol, 2005 Oct;99(7):695-714.
    PMID: 16212803
    Citridiol is an extract of the leaves of Corymbia citriodora (Myrtaceae), the lemon eucalyptus, and mostly consists of p-menthane-3,8-diol isomers. The effectiveness of this extract as a repellent against land leeches of the genus Haemadipsa (Haemadipsidae), primarily H. sylvestris, was tested in the laboratory and field, in Peninsular Malaysia. The formulation tested, Mosi-guard Natural spray, contained 40% (w/w) Citridiol in a base of ethanol, water and isopropanol. In the laboratory test, specimens of H. sylvestris that were placed within moist, untreated arenas enclosed by treated paper rings made numerous attempts to cross the rings but were prevented or delayed from crossing over, in a dose-dependent manner. Mortality was high among the leeches that attempted to cross over the paper rings that had been sprayed to saturation point but low among the leeches that attempted to cross over paper rings that had only been partially treated, with a droplet-spray. The field study was carried out using indices that were formulated to reflect the severity of leech attack and the degree of repellency. Heavy or moderate spraying of footwear and trouser legs (tucked into socks) not only gave complete protection against bites by H. sylvestris and H. picta but also provided high enough repellency to keep the treated footwear virtually free of leeches. Even a light spray greatly reduced the numbers of leeches on footwear and delayed their progression toward biting the test subjects, although it failed to prevent bites completely. There was no decline in the repellency of the Citridiol when hourly assessments were made over a 6-h test period in the field. The results of the study show that Citridiol is highly repellent as well as toxic to leeches, and can be effectively used to prevent leech bites in the field.
  8. Chang MS
    Ann Trop Med Parasitol, 2002 Dec;96 Suppl 2:S71-6.
    PMID: 12625920
    An estimated 13 million people in the Oriental Region have brugian filariasis. The filarial parasites that cause this disease exist in periodic and sub-periodic forms and are transmitted by four genera of mosquito: Anopheles, Mansonia and, less frequently, Coquillettidia and Ochlerotatus. In most endemic countries, control of the disease has been entirely based on chemotherapy, although house-spraying and use of insecticide-treated bednets can be quite effective against the vectors of nocturnally periodic Brugia malayi and B. timori. The vector-control methods that may be applied against the Mansonia mosquitoes that transmit the parasites causing sub-periodic brugian filariasis are reviewed here. Most of the conventional methods for controlling the immature, aquatic stages of mosquitoes have proved unsatisfactory against Mansonia. The reason is that, unlike the those of other genera, the larvae and pupae of Mansonia spp. are relatively immobile and obtain air not at the water surface but from the underwater roots, stems and leaves of floating plants to which the larvae and pupae attach. Removal of host plants can be very effective in reducing Mansonia productivity, whereas large-scale use of herbicides is restricted by the potential adverse effects on the ecosystem. Environmental management in water-development projects remains the best option.
  9. Le TH, Blair D, McManus DP
    Ann Trop Med Parasitol, 2002 Mar;96(2):155-64.
    PMID: 12080976
    Recent electrophoretic data have indicated that Schistosoma japonicum in mainland China may be a species complex, with the existence of a cryptic species being predicted from the analysis of schistosome populations from Sichuan province. To investigate the Sichuan form of S. japonicum, 4.9 kbp of mitochondrial DNA from each of three samples of the parasite from China (two from Sichuan and one from Hunan) and one from Sorsogon in the Philippines were amplified, sequenced and characterized. The sequence data were compared with those from the related South-east Asian species of S. mekongi (Khong Island, Laos) and S. mlayensis (Baling, Malaysia) and that from S. japonicm from Anhui (China). At both the nucleotide and amino-acid levels, the variation among the five S. japonicum samples was limited (< 1%). This was consistent with the conclusions drawn from previous molecular studies, in which minimal variation among S. japonicum populations was also detected. In contrast, S. mekongi and S. malayensis, species recognized as separate but closely related, differ from each other by about 10%, and each differs by 25%-26% from S. japonicum. Phylogenetic trees provided a graphic representation of these differences, showing all S. japonicum sequences to be very tightly clustered and distant from S. mekongi and S. malayensis, the last two being clearly distinct from each other. The results thus indicate no significant intra-specific genetic variation among S. japonicum samples collected from different geographical areas and do not support the idea of a distinct form in Sichuan.
  10. Jaal Z, MacDonald WW
    Ann Trop Med Parasitol, 1992 Aug;86(4):419-24.
    PMID: 1463364
    In a coastal village in northwest Malaysia, 3231 fed Anopheles females of eight to 10 species were collected, marked with fluorescent dust, and released on three consecutive nights. In collections made on the 10 nights after the first release, 58 mosquitoes of three species, An. lesteri paraliae, An. subpictus and An. vagus, were recaptured; the recapture rates were 3.42%, 1.19% and 0.97%, respectively. The data for An. subpictus and An. vagus were insufficient for further analysis. Those for An. l. paraliae were plotted against time of recapture and, from the regression coefficient, an estimate of 0.68 was obtained for the daily survival rate. An independent estimate based on the parous rate during the previous year was 0.55. The temporal distribution of the recaptures strongly suggested a gonotrophic cycle and oviposition cycle of two days.
  11. Fox MT, Jacobs DE, Sani RA
    Ann Trop Med Parasitol, 1991 Apr;85(2):263-7.
    PMID: 1796870
    Blood gastrin and pepsinogen responses of native village goats in Malaysia to a single dose of 10,500 infective Haemonchus contortus larvae were investigated. Both blood values were significantly elevated within a week of infection and exhibited a highly significant correlation during the study. The magnitude of the blood gastrin response was, however, significantly greater than that of pepsinogen during the period that both blood values were elevated. It is suggested that blood gastrin assay may be of particular value in the diagnosis of chronic haemonchosis in animals harbouring relatively light worm burdens.
  12. Khoo KK
    Ann Trop Med Parasitol, 1981 Dec;75(6):591-5.
    PMID: 7325735 DOI: 10.1080/00034983.1981.11687489
    One hundred and nine (9·8%) out of 1103 malaria patients examined in Sabah were deficient in glucose-6-phosphate dehydrogenase (G6PD). Sixty-nine of these G6PD-deficient patients were randomly allocated to one of three treatment regimes with (a) chloroquine, (b) chloroquine and primaquine or (c) sulfadoxine-pyrimethamine (Fansidar). No haemolysis was observed in group (a); except for a single mild case, no haemolysis was seen in group (c). However, in the primaquine group (23 patients), haemolysis occurred in seven of the 16 patients who had complete G6PD deficiency. Of these seven, five required blood transfusion and the other two developed acute renal failure, one requiring peritoneal dialysis. In the Fansidar group (c), four of the 22 patients took more than 15 days to clear the parasitaemia. Chloroquine resistance to falciparum infection was common in the patients given this anti-malarial.
    Study site: Queen Elizabeth Hospital, Kola Kinabalu, Sabah, Malaysia
  13. Sinniah B, Leopairut J, Neafie RC, Connor DH, Voge M
    Ann Trop Med Parasitol, 1991 Dec;85(6):625-35.
    PMID: 1811440
    Enterobius worms or their eggs, or both, are present in preserved tissue sections or tissue specimens of 259 patients whose medical records are on file at the Armed Forces Institute of Pathology, Washington D.C., U.S.A. The most common site of infection (86.5%) was found to be the lumen of the appendix, where the worms provoke no reaction. Of the 259 patients 11 (4.2%) had worms and/or eggs in granulomas of the abdominal and pelvic peritoneum, and an equal number had granulomas on the peritoneum of the salphinx or on the surface of the ovary. There were also ectopic worms and/or eggs in granulomas on the peritoneum of the small and large intestines (2.7%). These Enterobius granulomas form around degenerating adult worms, around discrete eggs, around clusters of eggs, and, we believe, also around the tracks of migrating worms. Three patients (1.2%) had worms in perianal abscesses. A necrotic granuloma, removed from the lung of one patient, surrounded a degenerating adult worm. This suggests that the worm, carried to the lung as an embolus, impacted in a pulmonary arteriole. A stool specimen of one patient contains eggs of Enterobius, and that of another patient contains an adult Enterobius. This is the largest recorded histopathological study of enterobiasis in man.
  14. Hii JL, Kan S, Vun YS, Chin KF, Tambakau S, Chan MK, et al.
    Ann Trop Med Parasitol, 1988 Feb;82(1):91-101.
    PMID: 3041932
    Holoendemic malaria transmission in two small isolated forest communities and a coastal village was studied by (1) all night human bait collections of Anopheles species from inside and outside houses and (2) buffalo-biting and CDC light-trapping catches during March and November 1984. During the same period thick and thin blood films were collected from the human population, and spleen rates were determined in children from two to nine years of age. Using both the immunoradiometric assay (IRMA) and the dissection technique, more sporozoite-positive infections were detected in An. balabacensis and An. flavirostris in November than in March. IRMA confirmed the presence of Plasmodium falciparum sporozoites. An average of 76.2% of the An. balabacensis population lived long enough to have reached a point where infectivity with P. falciparum was possible in November. Although fewer than five adult females bit humans per night at any time, a resident could theoretically have received more than 160 infective bites in one year. A high frequency of feeding on humans, coupled with increased anopheline life expectancy, contributed to high estimates of falciparum malaria vectorial capacity (number of infections distributed per case per day); for An. balabacensis (1.44-7.44 in March and 9.97-19.7 in November) and for An. flavirostris (0.19-5.14 in March and 6.27-15.8 in November). These high values may explain the increased malaria parasite rates obtained from at least two forest communities. Correlation between actual and calculated rates of gametocytaemia was poorest in Kapitangan due to inadequate sampling of the human population. In Banggi island, malaria is stable and holoendemic, and the population enjoys a high degree of immunity.
  15. Chiang GL, Samarawickrema WA, Eng KL, Cheong WH, Sulaiman I, Yap HH
    Ann Trop Med Parasitol, 1986 Apr;80(2):235-44.
    PMID: 2875691
    Surveillance methods for Coquillettidia crassipes were studied in an open housing estate near Kuala Lumpur using three types of traps Trinidad 10 trap, modified Lard can trap and IMR trap, each baited with chicken or pigeon. All traps attracted Cq. crassipes. There was no significant difference in the catches in the three traps. There was also no significant difference between chicken and pigeon as bait. Catches at heights of 1.5, 3, 4.5 and 6 m did not show any significant difference in density. Cq. crassipes was active at night with an early peak during the first hour of the night and a minor peak between 0100 and 0200 hours. The activity of the parous and nulliparous sections of the population was similar, except that a higher proportion of the parous females was active during the second peak compared with the nulliparous females. The parous rate was 22.3%, and the probability of survival through one day for two gonotrophic cycles was 0.711 and 0.650. The infection rate for Cardiofilaria was 29 out of 1052 (2.76%) and the infective rate (L3 larvae) was 13 out of 1052 (1.24%). 48.3% of the infected Cq. crassipes had a worm burden of more than ten larvae. One of the chickens in the traps was positive for microfilariae of Cardiofilaria four weeks after exposure as bait. Laboratory bred Cq. crassipes fed on this chicken produced infective larvae in ten days, and these were inoculated into clean chickens and pigeons. Microfilariae appeared in the chickens but not in pigeons. The adult worms recovered await identification.
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