Infection In Tropical Countries Research Articles

Immune Thrombocytopenia Following Dengue Fever

Introduction: Dengue is an endemic mosquito-borne infection in tropical countries. The manifestations vary from asymptomatic infection to classic dengue fever, to more critical forms like dengue hemorrhagic fever and dengue shock syndrome. The critical phase occurs typically within the timeline of 4-7 days from the onset of symptoms. Case Report: We, hereby, report the case of a 7-year-old girl child who initially recovered from classic dengue fever. However, she was readmitted 18 days after the onset of initial symptoms with major bleeding manifestations due to immune thrombocytopenia responding to intravenous immunoglobulin. Discussion: Dengue fever may be associated with mild to moderate thrombocytopenia in the febrile phase and moderate to severe thrombocytopenia in the critical phase. Here, the index case developed thrombocytopenia much after the expected critical phase was over. Conclusion: Awareness of this possibility and continued monitoring, even after apparent recovery from dengue, is important for detecting and managing late-onset thrombocytopenia.

Identification and Clinical Characteristics of Community-Acquired Acinetobacter baumannii in Patients Hospitalized for Moderate or Severe COVID-19 in Peru.

Acinetobacter baumannii has been described as a cause of serious community-acquired infections in tropical countries. Currently, its implications when simultaneously identified with other pathogens are not yet adequately understood. A descriptive study was conducted on hospitalized patients with a diagnosis of moderate/severe SARS-CoV-2-induced pneumonia confirmed via real-time RT-PCR. Patients aged > 18 years who were admitted to a specialized COVID-19 treatment center in Peru were selected for enrollment. A. baumannii was detected via the PCR amplification of the blaOXA-51 gene obtained from nasopharyngeal swabs within 48 h of hospitalization. A total of 295 patients with COVID-19 who met the study inclusion criteria were enrolled. A. baumannii was simultaneously identified in 40/295 (13.5%) of COVID-19-hospitalized patients. Demographic data and comorbidities were comparable in both Acinetobacter-positive and -negative subgroups. However, patients identified as being infected with Acinetobacter were more likely to have received outpatient antibiotics prior to hospitalization, had a higher requirement for high-flow nasal cannula and a higher subjective incidence of fatigue, and were more likely to develop Acinetobacter-induced pneumonia during hospitalization. Conclusions: The group in which SARS-CoV-2 and A. baumannii were simultaneously identified had a higher proportion of fatigue, a higher frequency of requiring a high-flow cannula, and a higher proportion of superinfection with the same microorganism during hospitalization.

Analysis of Trends in Dengue Infection among Patients Attending a Tertiary Care Teaching Hospital: A Retrospective Observational Study

Introduction: Dengue, a common mosquito-borne arboviral infection in tropical countries, presents cyclical epidemics and seasonal variations with diverse clinical outcomes. Over the past three decades, it has become endemic in India, leading to a rising mortality trend, primarily due to its severity and antibody-dependent enhancement in secondary dengue cases. Therefore, understanding the trend of dengue infection in specific geographical areas is crucial for more efficient prophylaxis. Aim: To provide a comprehensive overview of the seroprevalence of dengue virus infection in Surat district, including the trends in gender, age distribution, and seasonal variations of dengue infection from 2014 to 2021. Materials and Methods: The present retrospective observational analysis was conducted in the Department of Microbiology, Government Medical College (tertiary care teaching New Civil Hospital), Surat, Gujarat, India. A total of 31,683 blood samples were received from patients with clinical suspicion of dengue-like illness from January 2014 to December 2021. Data collection took place from March 2022 to May 2022, and the analysis was conducted in June and July 2022. All samples underwent dengue infection detection using the Enzyme-linked Immunosorbent Assay (ELISA) method by Non structural 1 (NS1) antigen detection and Immunoglobulin M (IgM) antibody detection by Mac capture ELISA. Demographic and clinical details were obtained and recorded from laboratory request forms using a structured data sheet in using Microsoft Excel software version 2013. The data were entered and analysed using EpiInfo software version 3.5.1. Results: Among the 31,683 blood samples tested, 5,994 (18.91%) cases were confirmed for dengue infection through ELISA testing. The highest number of positive cases (33.6%) was observed in the 20-29 years age group, with males outnumbering females in terms of dengue positivity at a ratio of 1.37:1. The maximum number of dengue cases occurred during the postmonsoon and early winter periods, with 96.5% of cases reported from Surat district, India. Conclusion: The rising trend of dengue infection in different age groups over the years underscores the need for continued implementation of surveillance and preventive strategies before the monsoon, aiming to reduce severe dengue infections in the future.

Ascaris lumbricoides, an uncommon cause of appendicitis

Appendicitis is the first cause of acute abdomen. There are many causes of appendicitis, one of them is parasites, and, Ascaris is the most common helminth infection in tropical countries (Asia, Africa, South America). Ascaris, once it is ingested, lives at the digestive tract and it can end up in the appendix lumen and lead to appendicitis by luminal obstruction, in fact this presentation is rare and is still debatable in the literature. Diagnostic most of times is made retrospectively by the demonstrations of ascaris eggs on the pathological examination of the appendix. We present the case of 7 years old male that arrives to emergency room presenting clinically acute appendicitis with 24 hours from beginning with fever 38ºC, intense mesogastrium abdominal pain with migration to right lower quadrant, anorexy, without nausea or vomiting, normal vital signs at physical examination intense abdominal pain, rebound, positive McBurney and psoas sign, leukocytosis with sift left. He underwent to emergency operation because suspect of appendicitis, we found a cecal appendix with Ascaris lumbricoides parasite in its lumen.

Genetic Comparison of H3N2 Influenza Virus in Indonesia with WHO Recommended Strains During the Period 2004 – 2021

Influenza caused by A/H3N2 virus is one commonly found infections in tropical countries. Vaccination policy against A/H3N2 virus is already established for Northern and Southern hemisphere, however, no specified policy is established for tropical countries such as Indonesia. World Health Organization (WHO) has recommended Indonesia to use vaccine formulation designated for Northern hemisphere. Some studies, however, have shown that there were mismatches between recommended vaccine and circulating strains present in Asian countries, which might have caused regional outbreaks. This study was aimed to compare the genetic makeup of WHO recommended vaccine strain with H3N2 virus circulating in Indonesia. A total of 147 HA and 148 NA complete nucleotide sequences from Indonesian population, as well as 14 HA and 14 NA WHO-recommended nucleotide sequences, were downloaded from GISAID. These sequences were subjected to phylogenetic analysis using MEGA 11. Furthermore, antigenicity of these isolates was analyzed using Kolaskar and Tangonkar Prediction method accessible through IEDB website and Vaxijen 2.0. This study revealed that WHO-recommended vaccine strain for southern hemisphere in 2010 were compatible with Indonesian strains circulating in 2009. Furthermore, there were no recommended vaccine strain that matched strain in circulation between 2010 to 2012 and 2019. Kolaskar and Tongaonkar antigenicity prediction analysis had simulated that several mutations rendered some antigenic epitopes of HA and NA protein to be non-antigenic. These findings highlighted the importance of reliable national surveillance network of influenza to prevent regional epidemic and the development of local influenza vaccine to better accommodate Indonesian population.

Dengue seroprevalence study in Bali.

Dengue infection poses significant public health problems in tropical and subtropical regions worldwide. The clinical manifestations of dengue vary from asymptomatic to severe dengue manifestations. This serological survey highlighted the high incidence of asymptomatic cases. This study aimed to determine the prevalence of dengue in healthy and ill adults in Bali. Cross-sectional seroprevalence surveys were performed between July 2020 and June 2021 among healthy and ill adults in Denpasar Bali. Blood samples were collected from 539 randomly selected urban sites in Denpasar. Immunoglobulin G antibodies against the dengue virus were detected in serum using a commercial enzyme-linked immunosorbent assay kit. Overall, the dengue seroprevalence rate among the 539 clinically healthy and ill adults was high (85.5%). The median age was 34.1 (18-86.1). Most of the participants in the study were younger than 40 years (61.2%). Men were the dominant sex (54.5%). The study found a significant association between dengue seropositivity among people aged > 40 years and healthy status (p = 0.005; odds ratio [OR] = 0.459 and p < 0.001; OR = 0.336, respectively). The study reported that as many as 60% of the subjects had a history of previously suspected dengue infection. This study reflected the proportion of asymptomatic dengue patients requiring better assessment with a serological test. The current study highlighted that real cases of dengue infection may be higher than reported, with a high prevalence of dengue seropositivity and a relatively dominant proportion of asymptomatic cases. The study guides physicians to be aware of every dengue infection in tropical countries and prevent the spread of the disease.

Seroprevalence of porcine reproductive and respiratory syndrome virus on swine farms in a tropical country of the Middle Americas: the case of Costa Rica

Porcine reproductive and respiratory syndrome virus (PRRSV) causes significant economic losses to the swine industry worldwide. Little is known regarding the epidemiology of this infection in tropical countries. To address this problem in Costa Rica, a seroepidemiological study was carried out in two phases. In the first phase, a pilot study was conducted in nine farms with the clinical diagnosis of PRRSV. In total, 265 pig serum samples were collected from animals ranging in age from 1 to 15 weeks of age. This study aimed to establish the duration of maternal immunity in piglets, to identify the period of viremia, and to determine when seroconversion occurs. In the second phase, a cross-sectional serology study was performed on a representative sample of the Costa Rican national herds in the second phase. The twenty-five selected farms represent all provinces and were classified according to herd size (100 to 2000 sows). In each farm, pigs aged 8, 10, and 12 weeks were sampled, as well as gilts based on the pilot study. In total 1281 pigs were sampled across all 25 farms. The aim of the cross-sectional study was to quantify the seroprevalence of PRRSV in Costa Rican pig farms and to describe its geographical distribution in this tropical country. The prevalence of positive farms was 44% (11/25), and these farms were located in six of the seven provinces of Costa Rica. Overall, 58% (344/596) of the pigs were seropositive to PRRSV. The age of the pigs and the ecozone where farms were located were significantly related with PRRSV seroprevalence in animals and herds, respectively.

Cysticercosis Lesions in Submandibular Region, Masseter and Abdominal Wall in the Same Patient: A Case Report.

Cysticercosis is a common infection in tropical countries with occasional uncommon manifestations. We present the case of a 34year old immunocompetent man who presented with multiple lesions in a short span of time, some of which were atypical in location viz submandibular region and masseter, aside from abdominal wall. Role of ultrasound, fine needle aspiration cytology and magnetic resonance imaging in diagnosis is discussed. Cysticercosis is a common disease with occasionally unexpected manifestations and hence must be considered in differential diagnoses of swellings in/around head and neck. There should be a low threshold for obtaining ultrasound and fine needle aspiration cytology in such swellings.

Dengue hemorrhagic fever as a rare cause of chronic immune thrombocytopenic purpura\u2014a pediatric case report

BackgroundDengue is a common mosquito-borne infection in tropical countries. Dengue incidence in Sri Lanka is generally showing a rising trend. Both chronic immune thrombocytopenia purpura (ITP) children and chronic ITP triggered by dengue fever in the pediatric age group are rarely reported. This unusual presentation is a diagnostic challenge to clinicians. The authors have reported a pediatric patient who presented with chronic ITP following recovery from dengue hemorrhagic fever.Case presentationA 14-year-old previously healthy boy was initially managed as for dengue hemorrhagic fever. Following initial detection of persistent thrombocytopenia at 2 weeks post-discharge, his parents defaulted follow-up for 1 year as he remained asymptomatic. However, 1 year after initial admission, the child re-presented with ecchymotic patches and a platelet count of 30 × 103/cumm. Review of serial blood counts performed during previous hospital admission and by his parents themselves revealed persistent thrombocytopenia over preceding 12 months. Subsequently, the child had an in-depth evaluation. The diagnosis of ITP was confirmed by ruling out differential diagnosis and he was managed as for chronic ITP. His platelet counts showed good response to oral corticosteroids and he is currently being followed up at the pediatric hematology clinic.ConclusionWhile reporting, a 14-year-old boy who developed chronic ITP following dengue hemorrhagic fever, this report highlights importance of frequent monitoring of blood counts to accurately detect and manage critical phase of dengue fever. The report also highlights the value of monitoring platelet counts in post-recovery phase to ensure they have normalized.

Invasive Fungal Infections of the Central Nervous System in Immune-Competent Hosts

Fungal infections of the central nervous system (CNS) occur more commonly in immunosuppressed individuals. However, they are being recognized in apparently immune-competent hosts in recent times. Understanding the risk factors, characters of the fungus, and pathogenesis is important. Fungal infections of CNS in apparently immune-competent hosts are described following neurosurgical procedures, head trauma, patients exposed to contaminated devices/drugs, or natural disasters. Disruption of the meninges and blood-brain barrier and direct inoculation of the fungal spores into the subarachnoid space are implicated in the pathogenesis. Contamination of drugs used for epidural injections resulted in an epidemic of fungal meningitis by a dematiaceous fungus, which was never reported earlier to cause CNS disease. Certain fungi like Coccidioides, Paracoccidioides, Histoplasma, and Blastomyces are endemic and the high concentrations in the environment and exposure are risk factors for invasive infections. Heavy and constant exposure in hot and humid climate is responsible for Aspergillus flavus infections in tropical countries. Some fungi such as Cryptococcus spp. and dematiaceous fungi are neurotropic. Environmental, genetic, and socioeconomic factors are also implicated. The exact pathogenesis remains unclear. The intense inflammatory response elicited by immune-competent hosts is likely to result in host damage. Sub-optimal health care facilities in developing countries along with environmental and climatic changes likely result in invasive infections in immune-competent hosts. Awareness of invasive fungal infections in immune-competent host with uncommon clinical presentation and uncommon etiological agents is important for early diagnosis.

Quantitative profiling of tear proteome reveals down regulation of zinc alpha-2 glycoprotein in Aspergillus flavus keratitis patients

Corneal mycotic ulceration is predominantly due to Aspergillus and Fusarium solani infection in tropical countries. In this study, we examined the proteome profile of tear samples from A. flavus keratitis patients at various stages of infection. The proteome was profiled using 2D PAGE and the protein levels were quantified using 2D DIGE. Alpha-1-antitrypsin, apolipoprotein, haptoglobin, lactoferrin and albumin were up regulated while cystatin SA III precursor, lacrimal lipocalin precursor, lacritin precursor and Zinc alpha-2 glycoprotein (ZAG) were down regulated in tear fluid. In the case of ZAG all proteoforms were down regulated as the disease progressed from early to late stage of infection. Western blot analysis confirmed the results observed using DIGE. Further, there were no gender specific differences in the levels of ZAG expression in keratitis patient tear film. Published results show up regulation of ZAG in Fusarium keratitis patient tear indicating subtle changes in the early events of host response to these two fungal pathogens. We conclude that ZAG level could be used as an indicator of A. flavus or F. solani infection, even during the early stage of the disease.

Sera-epidemiology of Dengue Virus Infection in Clinically Suspected Patients Attended in Dhaka Medical College Hospital During January to December 2016

Introduction: Dengue is now established as one of the most important Arboviral infection in tropical countries. As the epidemic continues worldwide, this Aedes mosquito-transmitted pathogen is considered a major re-emerging tropical disease and significant public health concern. The study was conducted to determine the sero-epidemiology and clinical picture of dengue virus infection among the clinically suspected patients attended in Dhaka Medical College Hospital during January to December 2016.Materials and Methods: The study was carried out on 145 clinically suspected Dengue patients attended in Dhaka Medical College Hospital from January to December 2016 who had fever with temperature &gt;39°C. Blood sample was collected during acute febrile phase of patients and separated sera were tested for NS1 dengue antigen and IgM antibodies using commercial test kits (NS1 by OMC Healthcare (Pvt.) Ltd &amp; IgM antibody by Omega Diagnostics Ltd.).Results: Of the total 145 patients 40 (27.6%) were positive for Dengue NS1 antigen and or IgM antibody test. Of the positive 40 patients, 18 (45%) were positive for NS1, 19 (47.5%) were positive for IgM and 3 (7.5%) were positive for both NS1 and IgM antibody. Major clinical manifestations were fever with arthralgia (79.5%) and retro-orbital pain (50%).Conclusion: Outbreak of Dengue fever is continuing every year and typical presentation of Dengue fever has changed. Arthralgia and retro orbital pain was the most common clinical feature in the present study instead of headache and rash with fever. A large number of suspected dengue cases were negative by Dengue tests for antigen NS1 and IgM antibody which suggests other organisms of similar clinical manifestations are becoming prevalent in Dhaka city.J Dhaka Medical College, Vol. 26, No.2, October, 2017, Page 111-116

Epidemiology and factors influencing varicella infections in tropical countries including Sri Lanka.

Varicella zoster virus (VZV) infections occur worldwide but the epidemiology differs between different geographical regions. Epidemiology of varicella is partly understood in tropical and subtropical regions. Various hypotheses showing differences in exposure rates in different age groups have been proposed. Exposure to VZV during late childhood or adolescent stage causes high morbidity, especially in high school children, university students and young work force in tropical nations. Exposure to VZV infection or sero-prevalence rates through anti-VZV immunoglobulin G appears to be lower in Sri Lanka, similar to other tropical countries prior to the millennium. In contrast, a more recent study in a group of antenatal women showed a relatively higher exposure rate to VZV when compared to the exposure rates prior to 2004 in Sri Lanka. Climatic factors, socioeconomic conditions, mobility and cultural practices appear to play a role in the differences in the exposure rates to VZV infection in the tropics. In most tropical Asian countries including Sri Lanka, routine vaccination against varicella is not carried out. Individuals with negative history for varicella take the vaccine when there is a necessity. Medical and nursing students take the vaccine prior to their clinical training to avoid adulthood varicella.

Controlling Dengue: Effectiveness of Biological Control and Vaccine in Reducing the Prevalence of Dengue Infection in Endemic Areas

With the increased prevalence of dengue infection in tropical countries, concerned members of the public are now pressing their local health ministries to act immediately and effectively in managing the rising numbers of reported cases. This includes reviews of the methodologies and the effectiveness of current combative systems to find other possible novel approaches that might yield better results. One of those novel approaches is the integration of a parasite into mosquito vector, manipulating the parasite-host interaction to reduce the transmission of dengue in endemic hotspots. Another alternative is by Sanofi-Pasteur’s dengue vaccine that showed over 60.8% success rate in reducing severe dengue infection in children aged 9 - 16 during its final clinical implementation phase. This report will compare and contrast these two novel ideas to determine which of the approaches are more likely to be effective in the long run. The aspects covered will include the application, effectiveness, functionality, and problems with these approaches. The results could then be utilised by governments or organizations to select precise and effective methods in reducing the prevalence of dengue infections in their countries.

Biliary Ascariasis Mimicking Biliary Sludge on Abdominal Ultrasonography: Diagnosis and Worm Extraction by Snare During Side-Viewing Endoscopy at ERCP

Introduction: Biliary ascariasis is a common parasitic infection in tropical countries, but is relatively rare in the United States. Common clinical presentations include biliary colic, acute cholangitis, acute cholecystitis, acute pancreatitis, or hepatic abscesses. A case is reported of the worm producing abnormal liver function tests, mimicking biliary sludge on abdominal ultrasound, and being successfully extracted during endoscopic retrograde cholangiopancreatography (ERCP). Case report: A 53-year-old female, immigrant to the United States from Bangladesh with prior cholecystectomy, and biliary sphincterotomy for cholelithiasis presented complaining of progressive abdominal pain for one month. Physical examination revealed a soft, nontender abdomen. The leukocyte count=16,100/mm3, with 14,300/mm3 neutrophils, and no eosinophilia. The serum alkaline phosphatase= 321 U/L, aspartate aminotransferase=428 U/L, alanine aminotransferase=232 U/L, total bilirubin= 1.5 mg/dl, and direct bilirubin=0.7 mg/dl. Serologies for viral hepatitis were all negative. Smooth muscle antibody, anti-mitochondrial antibody, celiac disease screen, and stool for ova and parasites were all negative. Abdominal ultrasound revealed a mildly dilated common bile duct (CBD) measuring 9 mm, containing a long segment, non-shadowing, echogenic material thought to represent sludge (Figure 1). Abdominal computed tomography and magnetic resonance cholangiopancreatography revealed extrahepatic dilatation attributed to the prior cholecystectomy. Endoscopic viewing before cannulation during ERCP revealed a curvilinear projection from the ampulla initially interpreted as a biliary stent. Closer examination showed the projection was a 12-cm-long nematode projecting from the ampulla (Figure 2), which was completely removed by snare. After cannulation, the CBD measured 10 mm in diameter. Sequential balloon pull-through resulted in extracting biliary sludge. Final occlusion cholangiogram did not reveal any residual filling defects. An expert parasitologist identified the nematode as an adult Ascaris lumbricoides. Patient was treated with one dose of albendazole 400 mg administered orally. The abdominal pain rapidly resolved and the liver function tests rapidly decreased towards normal before discharge.Figure 1Figure 2Discussion: This case report emphasizes that biliary ascariasis should be considered in the differential of chronic abdominal pain and abnormal liver function tests in patients from endemic regions, that the worm may mimic biliary sludge during abdominal ultrasound, and that it may be diagnosed and treated by ERCP.

An Investigation of Intestinal Parasitic Infections Among the Asymptomatic Children in, Southern Ethiopia

Background: Children under five years, particularly aged 2-4 years (24-48 months), are more vulnerable to intestinal parasitic infections. This is because, children with this ages may contract infective agents during their intense activities, and adventures such as crawling or walking on bare ground, sand or grasses or eating mud/pica. Increased population density, lack of awareness, poor sanitation, and poor public health practices, and environmental sanitations, affect the prevalence of parasitic infection in tropical countries. Moreover, the prevalence of intestinal parasitic infections among the asymptomatic children aged under five is not well studied. Objectives: The objectives of this study was to investigate the prevalence of intestinal parasitic infections among the asymptomatic children aged 6-59 months in selected Southern Ethiopia including Gedeo, Amaro, Walyta and Kambata. Methods: A cross-sectional study was carried out and the sampling design combined multistage sampling methods including, both simple random sampling technique, population density and systematic random sampling techniques. The course of this study took over a period of 5 months, from September 2009 to January 2010. Study participants were estimated by convenient sampling method to include 406 asymptomatic children (217 females and 189 males) from the systematically selected households of the study sites. Parasitological diagnosis of the parasites was done using the standard parasite and ova method. A total of 406 stool specimens were examined by a direct microscopy using a normal saline (0.9%) and lugol’s iodine wet mount techniques to determine the infection of intestinal parasites and the analysis of the data was made manually using thematic framework method. Results: Of the total 406 study participants, 170 (41.9%) children were found to have single and double intestinal parasitic infections whilst 236 (58%) children were free from the suspected parasites. Ascaris, lumbricoides, amoeba spp, Giardia lamblia, Trichuris trichiura, hookworms spp, Strongyloides stercoralis, and Hymenolepis nana were identified in both single and double infections. Double infections were found in 19 (11.2%) asymptomatic children of the total positive cases and the rest were single infections. In both single and double infections, ascaris was found to be the most dominant infective agent accounted 111(59%) out of the total 187 parasitic load of infection, followed by amoeba spp.31 (16.6%) and Trichuris trichiura 17(9%). Higher proportions of infected age groups were 25-48 while the least infected age groups were 6-24 and 49-59 months. Concluding Remarks and Recommendations: This baseline study indicated higher prevalence of intestinal parasitic infections in the study area and therefore, much effort is remaining to fight against parasitic infection. Along with regular deworming intervention, health education including infection cycle, environmental sanitation, personal hygiene, use of potable water and proper use of latrine should be given due attention to prevent and control parasitic infections among children in both urban and rural areas.

Acute myocardial infarction being the presentation of dengue myocarditis

Dengue fever is one of the most common vector-borne viral infections in tropical countries. Myocarditis is an uncommon complication of severe dengue fever. Sometimes, dengue myocarditis masquerades as acute myocardial infarction. We report here a case of a 22-year-old female, who presented with acute chest pain five days after the onset of a febrile episode. Initially she was diagnosed as acute myocardial infarction depending on the biochemical and echocardiography evidence. However, later investigation confirmed she was suffering from myocarditis due to dengue fever, which mimicked acute myocardial infarction. A Medline search revealed only few other reported cases of dengue myocarditis that mimicked of acute myocardial infarction.

Isolated Bell's palsy – An unusual presentation of dengue infection

Dengue fever is a very common arthropod – borne infection in tropical countries. Neurological complications in dengue fever are relatively uncommon and among these, isolated cranial neuropathies have been reported only very rarely. We present an unusual neurological complication of Bell's palsy (lower motor neuron 7 th nerve palsy) associated with dengue infection. To the best of our knowledge, there have been very few documented cases of Flavivirus causing isolated Bell's palsy.

Influenza outbreaks in Singapore: epidemiology, diagnosis, treatment and prevention

With the recent influenza A/H1N1 2009 pandemic still spreading through global populations, there has been an increased focus on optimizing the prevention, diagnosis and treatment of influenza infections, as well as the epidemiology of the virus. Clinical and epidemiological data on influenza infections in tropical countries have been relatively sparse until fairly recently, and it is the aim of this review to close some of these gaps by examining the behavior of influenza viruses in the tropical Singaporean population.

Lymphatic filariasis in children: Clinical features, infection burdens and future prospects for elimination

Lymphatic filariasis (LF), a common parasitic infection in tropical countries, causes lymphoedema of limbs, hydrocele and acute attacks of dermato-lymphangio-adenitis. Recent advances in diagnosis have helped to recognize that LF infection is often acquired in childhood. Newly available diagnostic techniques like sensitive antigen and antibody assays, Doppler ultrasonography and lymphoscintigraphy have helped to understand the subclinical pathology caused by this infection, which was hitherto generally believed to be irreversible. Recent studies indicate that drugs used in the mass drug administration (MDA) programme under GPELF are capable of reversing the sub-clinical lymphatic damage in children and provide benefits other than interruption of transmission. Albendazole and ivermectin used in MDA are effective against soil-transmitted helminthic infections common in children in LF endemic areas. Thus MDA had other 'beyond LF' benefits in treated children including increased appetite, weight gain, greater learning ability and concentration, better school attendance and prevention of anaemia. MDA should no longer be viewed as a measure for interrupting transmission alone. Recent findings of reversibility of early lymphatic pathology in treated children indicate that both MDA and 'foot-hygiene' measures are effective strategies in preventing and managing morbidity. Programme managers should effectively utilize this information to strengthen their advocacy efforts to achieve high and sustainable coverage in MDA.