Malaria PCR Detection in Cambodian Low-Transmission Settings: Dried Blood Spots versus Venous Blood Samples

In the context of malaria elimination, novel strategies for detecting very low malaria parasite densities in asymptomatic individuals are needed. One of the major limitations of the malaria parasite detection methods is the volume of blood samples being analyzed. The objective of the study was to compare the diagnostic accuracy of a malaria polymerase chain reaction assay, from dried blood spots (DBS, 5 μL) and different volumes of venous blood (50 μL, 200 μL, and 1 mL). The limit of detection of the polymerase chain reaction assay, using calibrated Plasmodium falciparum blood dilutions, showed that venous blood samples (50 μL, 200 μL, 1 mL) combined with Qiagen extraction methods gave a similar threshold of 100 parasites/mL, ∼100-fold lower than 5 μL DBS/Instagene method. On a set of 521 field samples, collected in two different transmission areas in northern Cambodia, no significant difference in the proportion of parasite carriers, regardless of the methods used was found. The 5 μL DBS method missed 27% of the samples detected by the 1 mL venous blood method, but most of the missed parasites carriers were infected by Plasmodium vivax (84%). The remaining missed P. falciparum parasite carriers (N = 3) were only detected in high-transmission areas.     

Observations on the epidemiology of gastrointestinal and liver cancers in the Asia–Pacific region

Gastric cancer (GC) has long been thought to be an Asian type of cancer that is broadly associated with poverty, whereas colorectal cancer (CRC) has been thought to be a Western type of cancer associated with affluence. The incidence of GC has declined dramatically in the West but has a very high incidence in East Asia. The age‐standardized incidence rates (ASR) have also declined. The decrease in the incidence of GC is associated with the decrease in the prevalence of Helicobacter pylori (H. pylori) infection worldwide. The discrepancy between a high H. pylori infection rate and a low GC incidence is seen chiefly among southern Asians of Indian origin and has been aptly termed the “Indian enigma”. CRC is a new emerging cancer in this region. Some of the highest CRC ASR have been reported from Asian countries, in many of which it has now surpassed that of GC. Liver cancer is also an important cancer in the Asia–Pacific region. The highest ASR worldwide is reported from the Asian countries of Mongolia, Korea and Japan. The predominant underlying etiology across the region has been hepatitis B virus infection, except in Japan, where hepatitis C is an important cause of hepatocellular carcinoma (HCC). With mass vaccination of hepatitis B at birth and improved public health measures in many countries, hepatitis B and C are set to decline with time. However, the exponential increase in obesity and consequent non‐alcoholic fatty liver disease portends a future epidemic of fatty liver‐related HCC.     

Predictive factors by multivariate analysis for colorectal cancer in Malaysian patients undergoing colonoscopy

BACKGROUND: The majority of colorectal cancers are still diagnosed in patients who present with symptoms especially in countries where colorectal screening programs are not practised. The aim of our study was to determine the predictive factors for colorectal cancer in patients referred for colonoscopy. METHODS: A prospective study of 485 consecutive patients who underwent colonoscopy during a 22-month period was performed. All patients answered a detailed questionnaire. Indications for colonoscopy and the findings were recorded. RESULTS: The mean age of the study population was 55.7 +/- 14.7 years. There were 221 (45.6%) males and 264 (54.4%) females. Sixty-five (13.4%) were Malays, 298 (61.4%) were Chinese and 112 (23.1%) were Indians. Multiple backward stepwise regression analysis revealed that independent predictors for colorectal cancer (odds ratio [95% CI]) were the presence of rectal bleeding (4.3 [4.0-8.0]) and iron deficiency anemia (4.0 [3.6-10.2]). In those aged 50 and over, male gender (4.5 [2.2-9.3]) and abdominal pain (3.1 [1.4-6.7]) were also significant positive predictors of cancer. CONCLUSIONS: With the ever-increasing demand for gastrointestinal endoscopy, the appropriate utilization of colonoscopy is essential to afford prompt patient evaluation. Our study supports the need to prioritize the use of colonoscopy in patients with rectal bleeding and iron deficiency anemia. In the older patient where the background prevalence of colorectal cancer is higher, referral for colonoscopy is also justified.     

Relapsed and late-onset Nipah encephalitis

An outbreak of infection with the Nipah virus, a novel paramyxovirus, occurred among pig farmers between September 1998 and June 1999 in Malaysia, involving 265 patients with 105 fatalities. This is a follow-up study 24 months after the outbreak. Twelve survivors (7.5%) of acute encephalitis had recurrent neurological disease (relapsed encephalitis). Of those who initially had acute nonencephalitic or asymptomatic infection, 10 patients (3.4%) had late-onset encephalitis. The mean interval between the first neurological episode and the time of initial infection was 8.4 months. Three patients had a second neurological episode. The onset of the relapsed or late-onset encephalitis was usually acute. Common clinical features were fever, headache, seizures, and focal neurological signs. Four of the 22 relapsed and late-onset encephalitis patients (18%) died. Magnetic resonance imaging typically showed patchy areas of confluent cortical lesions. Serial single-photon emission computed tomography showed the evolution of focal hyperperfusion to hypoperfusion in the corresponding areas. Necropsy of 2 patients showed changes of focal encephalitis with positive immunolocalization for Nipah virus antigens but no evidence of perivenous demyelination. We concluded that a unique relapsing and remitting encephalitis or late-onset encephalitis may result as a complication of persistent Nipah virus infection in the central nervous system.