Displaying publications 1 - 20 of 93 in total

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  1. Nissapatorn V
    PMID: 20578449
    Toxoplasmosis has historically been considered one of the most important opportunistic infections detected in HIV/AIDS patients. The prevalence rates of latent Toxoplasma infections in HIV-infected patients has been found to vary greatly from 3% to 97%. Prevalence has been found to be related to ethnicity, certain risk factors, and reactivation of toxoplasmosis. Prior to antiretroviral therapy, toxoplasmic encephalitis (TE) was the most common focal cerebral lesion detected in AIDS patients with Toxoplasma infection, occurring in approximately half of Toxoplasma-seropositive patients. Other forms of dissemination have also been reported in AIDS patients in sites such as the eyes, lungs, heart and spinal cord. Anti-Toxoplasma therapy and chemoprophylaxis have shown effectiveness in reducing the incidence of TE, while noncompliance has been identified as a cause of relapse in these settings. Toxoplasmosis is one of the most common neuropathological complications found at autopsy. Rapid progress in the development of highly active antiretroviral therapy (HAART) has changed the observed patterns with TE, for which there has been a marked decrease in overall incidence. Subsequently, TE has been found to be significantly associated with the so-called "neurological immune restoration inflammatory syndrome" (NIRIS). Toxoplasma screening programs are recommended for all newly diagnosed HIV-positive patients. Chemoprophylaxis should be considered in HIV-infected patients who have a CD4 < 200 cells/mm3, particularly in settings where resources are limited and there is not access to HAART. TE remains a cause of morbidity and mortality among AIDS patients.
  2. Nissapatorn V
    PMID: 19058599
    Southeast Asia is a region where the number of people infected with HIV/AIDS is one of the fastest growing in the world. Tuberculosis (TB) has grown along with the HIV epidemic. TB is not only the most common AIDS-defining illness but is also the leading cause of morbidity and mortality in AIDS patients. Cryptococcosis (meningitis or disseminated) is one of the most common opportunistic infections in AIDS patients. Cryptococcal meningitis is the first in the differential diagnosis considered with meningeal irritation. Penicillosis, a unique systemic mycosis, is an important emerging public health problem and has been classified as an AIDS defining illness in endemic areas like Thailand. Pneumocystis carinii (jiroveci) pneumonia has been one of the most important opportunistic infections in AIDS patients. Among parasitic infections, cryptosporidiosis is the most common intestinal protozoan infection relating to diarrhea in AIDS patients and toxoplasmosis is the only parasitic infection of the nervous system with a substantial incidence, up to 14.8%. Cytomegalovirus (CMV) retinitis has a lower prevalence compared to other opportunistic infections. In the era of highly active antiretroviral therapy (HAART), the incidence of opportunistic infections has significantly reduced in the past few years. Subsequently, the phenomena of immune restoration inflammatory syndrome (IRIS) in AIDS patients has been reported in this region as a result of HAART.
  3. Rohela M, Jamaiah I, Amir L, Nissapatorn V
    PMID: 17547059
    Many cases of myiasis have been reported in Malaysia. This is the second reported case of auricular myiasis caused by Chrysomya bezziana. The patient was a 41-year-old, mentally retarded, Orang Asli man. He was brought to the clinic by his mother with a complaint of pain and bleeding in his right ear for 3 days. On examination, blood and multiple maggots were seen packed in the external auditory canal of the right ear. A total of 39 live maggots were removed and maintained until they developed into 3rd instar larvae, which were later processed and identified as Chrysomya bezziana. The patient was discharged with amoxicillin 500 mg three times a day for 1 week.
  4. Josephine FP, Nissapatorn V
    PMID: 17547079
    We report a 68-year-old Indian man who was referred to the Hematology Unit for investigation for thrombocytopenia, an incidental finding during a pre-operative screening for prostatectomy. Physical examination was unremarkable. There was no splenomegaly, hepatomegaly or lymphadenopathy. Complete blood counts showed normal hemoglobin and total white cell count with moderate thrombocytopenia. Hairy-cell leukemia was diagnosed based on peripheral blood film, bone-marrow aspirate and trephine biopsy findings, supported by immunophenotyping results by flow cytometry. The purpose of this report is to create awareness of this uncommon presentation and to emphasize that a single-lineage cytopenia or absence of splenomegaly does not exclude the diagnosis of hairy-cell leukemia. Careful attention to morphological detail is important for early diagnosis, especially when low percentages of "hairy" cells are present in the peripheral blood and bone marrow. Early diagnosis is important to ensure that patients obtain maximum benefit from the newer therapeutic agents that have greatly improved the prognosis in this rare disorder.
  5. Josephine FP, Nissapatorn V
    PMID: 16438183
    This retrospective and descriptive study was carried out in the University of Malaya Medical Center (UMMC) from January to September, 2004. This study aimed to evaluate the diagnostic utility of the Cell-Dyn 4000 hematology analyzer's depolarization analysis and to determine the sensitivity and specificity of this technique in the context of malaria diagnosis. A total of 889 cases presenting with pyrexia of unknown origin or clinically suspected of malaria were examined. Sixteen of these blood samples were found to be positive; 12 for P. vivax, 3 for P. malariae, and 1 for P. falciparum by peripheral blood smear as the standard technique for parasite detection and species identification. Demographic characteristics showed that the majority of patients were in the age range of 20-57 with a mean of 35.9 (+/- SD) 11.4 years, and male foreign workers. Of these, 16 positive blood samples were also processed by Cell-Dyne 4000 analyzer in the normal complete blood count (CBC) operational mode. Malaria parasites produce hemozoin, which depolarizes light and this allows the automated detection of malaria during routine complete blood count analysis with the Abbot Cell-Dyn CD4000 instrument. The white blood cell (WBC) differential plots of all malaria positive samples showed abnormal depolarization events in the NEU-EOS and EOS I plots. This was not seen in the negative samples. In 12 patients with P. vivax infection, a cluster pattern in the Neu-EOS and EOS I plots was observed, and appeared color-coded green or black. In 3 patients with P. malariae infection, few random depolarization events in the NEU-EOS and EOS I plots were seen, and appeared color-coded green, black or blue. While in the patient with P. falciparum infection, the sample was color-coded green with a few random purple depolarizing events in the NEU-EOS and EOS I plots. This study confirms that automated depolarization analysis is a highly sensitive and specific method to diagnose whether or not a patient has malaria. This automated approach may prove to be particularly useful in situations where there is little or no clinical suspicion of malaria.
  6. Nissapatorn V, Abdullah KA
    PMID: 15272740
    We reviewed various studies regarding human toxoplasmosis in Malaysia. They showed a varying prevalence of specific Toxoplasma antibodies among the Malaysian population. The Malays have shown the highest seroprevalence of toxoplasmosis, by most studies, when compared to other races. Demographic profiles have shown that Toxoplasma seropositivity is higher in males than females, lower in people with higher incomes, higher in the unemployed and tends to increase with age. In general, the route of transmission, such as contact with a cat, consumption of undercooked meat and blood transfusion were shown to have no significant association with Toxoplasma seropositivity (p > 0.05). The immune status (CD4 cell count < 200 cell/mm3) was strongly associated with toxoplasmic encephalitis (p < 0.05).
  7. Chemoh W, Sawangjaroen N, Nissapatorn V, Sermwittayawong N
    Vet J, 2016 Sep;215:118-22.
    PMID: 27325616 DOI: 10.1016/j.tvjl.2016.05.018
    One of the most important routes of transmission for Toxoplasma gondii infection is the ingestion of foods contaminated with cat feces containing sporulated oocysts. The diagnosis of T. gondii infection by fecal microscopy is complicated, as other similar coccidian oocysts are often present in the same fecal specimen. This study aimed to identify T. gondii oocysts in cat feces using a novel PCR technique. Feline fecal specimens (n = 254) were screened for coccidian oocysts by light microscopy using the Sheather's flotation method. PCR analysis performed on the same specimens targeted a 529 bp repeat element and internal transcribed spacer-1 (ITS-1) regions were used to confirm the presence of Toxoplasma oocysts. By light microscopy, 49/254 (19.3%) of specimens contained coccidian oocysts. PCR analysis demonstrated 2/254 (0.8%) and 17/254 (6.7%) positive results using Tox and ITS-1 primers, respectively. However, coccidian oocysts were not identified on microscopic examination of specimens that were PCR-positive by Tox primers. Coccidian oocysts were identified on microscopic examination of 6/17 (35.3%) of the PCR-positive fecal specimens using ITS-1 primers. The BLAST results of 16 ITS-1 sequences were identified as T. gondii (n = 12; 4.7%) and Hammondia hammondi (n = 4; 1.6%). There was slight agreement between the 529 bp and ITS-1 PCR results (κ = 0.148). This is the first report of the detection of Toxoplasma oocysts using PCR analysis on feline fecal specimens from Southern Thailand. The ITS-1 region has potential as an alternative marker to identify T. gondii oocysts in feline fecal specimens.
  8. Nissapatorn V, Sawangjaroen N
    Indian J Med Res, 2011 Dec;134(6):878-97.
    PMID: 22310820 DOI: 10.4103/0971-5916.92633
    After 30 years of the human immunodeficiency virus (HIV) epidemic, parasites have been one of the most common opportunistic infections (OIs) and one of the most frequent causes of morbidity and mortality associated with HIV-infected patients. Due to severe immunosuppression, enteric parasitic pathogens in general are emerging and are OIs capable of causing diarrhoeal disease associated with HIV. Of these, Cryptosporidium parvum and Isospora belli are the two most common intestinal protozoan parasites and pose a public health problem in acquired immunodeficiency syndrome (AIDS) patients. These are the only two enteric protozoan parasites that remain in the case definition of AIDS till today. Leishmaniasis, strongyloidiasis and toxoplasmosis are the three main opportunistic causes of systemic involvements reported in HIV-infected patients. Of these, toxoplasmosis is the most important parasitic infection associated with the central nervous system. Due to its complexity in nature, toxoplasmosis is the only parasitic disease capable of not only causing focal but also disseminated forms and it has been included in AIDS-defining illnesses (ADI) ever since. With the introduction of highly active anti-retroviral therapy (HAART), cryptosporidiosis, leishmaniasis, schistosomiasis, strongyloidiasis, and toxoplasmosis are among parasitic diseases reported in association with immune reconstitution inflammatory syndrome (IRIS). This review addresses various aspects of parasitic infections in term of clinical, diagnostic and therapeutic challenges associated with HIV-infection.
  9. Lim YAL, Nissapatorn V
    Food Waterborne Parasitol, 2017 08 12;8-9:75-83.
    PMID: 32095642 DOI: 10.1016/j.fawpar.2017.08.001
    Most of the global outbreaks of waterborne parasitic protozoa have been reported in regions with established surveillance and reporting systems such as Australia, Europe, New Zealand, and North America. Given that only an estimated 1% of these outbreaks have occurred in Asia, it is evident that there is a paucity of information from this region where organised mechanisms of documentation of parasitic infections or waterborne outbreaks are lacking. This review attempts to provide an overview of the available data and studies on waterborne parasite occurrences among the Association of Southeast Asian Nations (ASEAN) which comprises of the ten member states (i.e., Brunei Darussalam, Cambodia, Indonesia, Lao People's Democratic Republic (PDR), Malaysia, Myanmar, the Philippines, Singapore, Thailand, and Vietnam) with the aims of identifying some directions on how to progress.
  10. Jetan CA, Jamaiah I, Rohela M, Nissapatorn V
    PMID: 20578521
    This was an eight year (2000-2007) retrospective study of tuberculosis in patients admitted to the UMMC. A total of 131 cases were analyzed. Malays constituted the most cases, (43%), followed by Chinese (22%), Indians (17%) and others (18%). The majority of cases were within the 21-60 year old age group, which constituted 69.5% of the total. Males were more commonly affected (65%). Most cases were reported among Malaysians (83%). The majority of patients were unemployed (39%), followed by housewives (10%), laborers (9%), students (8%), shop assistants (7%), and other occupations (27%). The most common presenting complaints were prolonged productive cough, night sweats, fever, anorexia, weight loss (57%), hemoptysis (34%), and undifferentiated symptoms, such as prolonged diarrhea and dysphagia (9%). Sputum was positive for acid-fast bacilli (AFB) in 89%, but only 69% of cases had abnormal chest radiographs. The majority of patients (65%) developed no complications. The most common complications were pleural effusion, pneumothorax and pulmonary fibrosis. The majority of patients (82%) suffered either from diabetes mellitus, hypertension, ischemic heart disease or all 3 conditions. Regarding risk factors for tuberculosis, two were HIV positive and two were intravenous drug users. The majority of the patients (85%) did not complain of any side effects from their anti-tuberculosis treatment. Among those who did complain of side effects, the most common were nausea and vomiting (41%), drug induced hepatitis (37%), blurring of vision (11%) and skin rashes (11%). Two cases of death were reported.
  11. Rohela M, Jamaiah I, Goh KL, Nissapatorn V
    PMID: 17333730
    Diphyllobothriasis was first reported in Malaysia in 2002. We are reporting a second case of diphyllobothriasis in Malaysia. The patient was a 37-year-old Chinese male seen at the outpatient clinic with a complaint of passing strands of white color flat worm in his stool. He had no other abdominal complaints. Laboratory and physical examinations were normal. Diphyllobothrium latum was confirmed by examination of the gravid proglottids passed out and the typical operculated eggs expelled from the ruptured proglottids. The patient had a history of eating raw fish. He was treated with a single dose of praziquantel.
    Study site: Outpatient clinic, University Malaya Specialist Center (UMSC), Kuala Lumpur, Malaysia
  12. Nissapatorn V, Lee CK, Rohela M, Anuar AK
    PMID: 15906630
    We retrospectively reviewed 205 HIV-infected patients, who came at first entry from January 2001 to December 2002 to the Hospital Kuala Lumpur, Kuala Lumpur, Malaysia. The aged range was 21-69 years [mean 37.25 years (+/- SD) 8.1]. Subjects were mainly in the age group 35-44 years. The majority of patients were male (82%), Chinese (55.1%), single (55.6%), resided in Kuala Lumpur (55.1%), and were unemployed (57.1%). The most frequent routes of transmission were sexual contact (78.5%), followed by IDUs (30%), blood transfusion (5%), and unknown (0.5%). Oral candidiasis was the most common mucocutaneous disease and significant co-existence was found with the main opportunistic systemic diseases, such as TB, PCP, toxoplasmic encephalitis, penicillosis, and CMV retinitis (p < 0.05). In this study, the range of CD4 counts was 0-910, with a median of 35 cells/mm3. Significant associations between a CD4 level less than 100 cells/mm3 at the time of diagnosis, and the occurrence of major opportunistic diseases, such as candidiasis, TB, PCP, TE, herpes simplex infection, CMV retinitis, penicillosis, and histoplasmosis were found (p < 0.05) in this study.
  13. Farhana F, Jamaiah I, Rohela M, Abdul-Aziz NM, Nissapatorn V
    Trop Biomed, 2009 Dec;26(3):262-6.
    PMID: 20237439 MyJurnal
    This is a ten year (1999-2008) retrospective study of amebiasis in patients admitted to UMMC. A total of 34 cases were analyzed. The most common were amebic liver abscess 22(65%) and the rest were amoebic dysentery 12(35%). Majority of the cases occurred among Malaysians 29(85%), with Chinese 14(41%), followed by the Malays 9(26%) and the Indians 6(18%). Foreigners made up of one Indonesian, one Pakistani and three Myanmarese and constituted 5(15%) of the total cases. Males 24(71%) were more commonly affected. Most of the cases occurred between the age group of 40-49 years, 8(23%) and 60 years and above, 8(23%). Age group of 20-50 years constituted 20(60%) of the cases. The most common clinical presentations were fever with chills and rigors 26(76%), diarrhoea 20 (59%), right hypochondrium pain 17(50%), abdominal pain 17(50%), hepatomegaly 16 (47%) and jaundice 7(20%). All were discharged well after treatment except for one case of death in a 69-year-old Chinese male with amebic liver abscess.
  14. Lim YA, Wan Hafiz WI, Nissapatorn V
    Trop Biomed, 2007 Jun;24(1):95-104.
    PMID: 17568382 MyJurnal
    Cryptosporidium and Giardia are two important pathogenic parasites that have caused many waterborne outbreaks which affected hundreds of thousands of people. Contamination from effluent discharged by sewage treatment plants have been implicated in previous waterborne outbreaks of Cryptosporidium and Giardia. This study evaluated the reduction of Cryptosporidium and Giardia (oo)cysts in two sewage treatment plants (STPA and STPB) in Malaysia which employed different treatment processes for a period of a year. Raw sewage influents and treated sewage effluents were concentrated by repeated centrifugation, subjected to sucrose density flotation and concentrated to a minimal volume depending upon the levels of contaminating debris. Cryptosporidium oocysts and Giardia cysts were enumerated using epifluorescence microscopy. The parasite concentrations in raw sewage were 18-8480 of Giardia cysts/litre and 1-80 of Cryptosporidium oocysts/litre. In treated sewage, the concentration of parasites ranged from 1-1462 cysts/litre and 20-80 oocysts/ litre for Giardia and Cryptosporidium respectively. Statistical analysis showed that sewage treatment process which employed extended aeration could reduce the concentration of Cryptosporidium and Giardia (oo)cysts significantly but treatment process which encompasses aerated lagoon could only reduce the concentration of Giardia cysts but not Cryptosporidium oocysts significantly. This phenomenon is of great concern in areas whereby effluent of sewage treatment plants is discharged into the upstream of rivers that are eventually used for abstraction of drinking water. Therefore, it is important that wastewater treatment authorities rethink the relevance of Cryptosporidium and Giardia contamination levels in wastewater and watersheds and to develop countermeasures in wastewater treatment plants. Further epidemiological studies on the occurrence and removal of pathogenic organisms from excreta and sewage are also recommended, in order that the public health risks can be defined and the most cost effective sewage treatment options developed.
  15. Nissapatorn V, Lee CK, Khairul AA
    Singapore Med J, 2003 Apr;44(4):194-6.
    PMID: 12952031
    Four hundred and six AIDS patients were recruited in this retrospective study. The seroprevalence of toxoplasmosis among 406 AIDS patients was 208 (51.2%). Their age ranged from 17 to 74 years with a median of 35 years. The majority of patients were males 172 (82.6%), Malays 99 (47.5%), single 109 (52.4%), unemployed 99 (47.6%) and heterosexual with commercial sex workers (CSW) 97 (46.6%) as the risk marker to HIV infection. Thirty-one (14.9%) of 208 AIDS-related toxoplasmosis were diagnosed as active toxoplasmic encephalitis. The most common clinical manifestation was headache (67.7%). The CT scan findings showed most lesions to be multiple (87.5%), hypodense (66.7%), and in frontal region (41.7%). Twenty-two (71%) patients had chronic (latent) Toxoplasma infection as evidenced by seropositivity for anti-Toxoplasma (IgG) antibody. They were statistically significant in the association between CD4 count and toxoplasmic encephalitis (P = 0.019; OR = 2.6; 95% CI = 1.14-6.02). After the initial six weeks of anti-TE therapy, relapsing toxoplasmic encephalitis was detected in 9.7% in this study.
  16. Nissapatorn V, Sawangjaroen N, Lee R, Chandra Parija S
    Biomed Res Int, 2014;2014:780715.
    PMID: 25587540 DOI: 10.1155/2014/780715
  17. Singh S, Khang TF, Andiappan H, Nissapatorn V, Subrayan V
    Trans R Soc Trop Med Hyg, 2012 May;106(5):322-6.
    PMID: 22480791 DOI: 10.1016/j.trstmh.2012.01.009
    Toxoplasma gondii is a public health risk in developing countries, especially those located in the tropics. Widespread infection may inflict a substantial burden on state resources, as patients can develop severe neurological defects and ocular diseases that result in lifelong loss of economic independence. We tested sera for IgG antibody from 493 eye patients in Malaysia. Overall age-adjusted seroprevalence was estimated to be 25% (95% CI: [21%, 29%]). We found approximately equal age-adjusted seroprevalence in Chinese (31%; 95% CI: [25%, 38%]) and Malays (29%; 95% CI: [21%, 36%]), followed by Indians (19%; 95% CI: [13%, 25%]). A logistic regression of the odds for T. gondii seroprevalence against age, gender, ethnicity and the occurrence of six types of ocular diseases showed that only age and ethnicity were significant predictors. The odds for T. gondii seroprevalence were 2.7 (95% CI for OR: [1.9, 4.0]) times higher for a patient twice as old as the other, with ethnicity held constant. In Malays, we estimated the odds for T. gondii seroprevalence to be 2.9 (95% CI for OR: [1.8, 4.5]) times higher compared to non-Malays, with age held constant. Previous studies of T. gondii seroprevalence in Malaysia did not explicitly adjust for age, rendering comparisons difficult. Our study highlights the need to adopt a more rigorous epidemiological approach in monitoring T. gondii seroprevalence in Malaysia.
  18. Chang PY, Fong MY, Nissapatorn V, Lau YL
    Am J Trop Med Hyg, 2011 Sep;85(3):485-9.
    PMID: 21896809 DOI: 10.4269/ajtmh.2011.11-0351
    Rhoptry protein 2 (ROP2) of Toxoplasma gondii is a rhoptry-secreted protein that plays a critical role in parasitophorous vacuole membrane formation during invasion. In previous studies, ROP2 has been shown to be efficient in triggering humoral and cell-mediated responses. High immunogenicity of ROP2 makes it a potential candidate for diagnosis and vaccination against toxoplasmosis. In this study, the ROP2 gene was cloned into pPICZα A expression vector and extracellularly expressed in the yeast Pichia pastoris, which has numerous advantages over other expression systems for eukaryotic proteins expression. The effectiveness of the secreted recombinant ROP2 as a diagnosis agent was assessed by Western Blot with 200 human serum samples. Recombinant ROP2 reacted with toxoplasmosis-positive human serum samples and yielded an overall sensitivity of 90% and specificity of 95%. However, recombinant ROP2 is a better marker for detection of IgG (91.7%) rather than IgM (80%).
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