Report of the Australian Malaria Register for 1992 and 1993

Australia is free from endemic malaria but several hundred imported cases occur each year. Notification and screening data on malaria cases are collected by State and Territory health authorities and laboratories and forwarded to the Australian Malaria Register (AMR) for national collation and analysis. This report provides information on 758 malaria cases with 5 deaths reported in Australia in 1992 and 712 cases with 1 death in 1993. In both years, just over 70% of cases were male and the modal age group was 20 to 29 years. Cases were reported from all States and Territories, with Queensland reporting the greatest number of cases in both years. The predominant species was Plasmodium vivax, although P. falciparum accounted for just over a quarter of the cases each year. Papua New Guinea (PNG) was the most common source of cases in both years, reflecting the number of people who move between Australia and PNG and the high endemicity of malaria in PNG. The incidence of malaria was also high in travellers from the Solomon Islands in both years and from Ghana in 1992 and Nigeria in 1993. The six deaths over two years highlight the need for medical practitioners to consider malaria as a diagnosis in patients with a history of travel to malarious countries and to provide appropriate advice on malaria prophylaxis to intending travellers.     

Modeling malaria as a complex adaptive system

As the resistance of the malaria parasite to antimalarial drugs continues to increase, as does that of the malarial mosquito to insecticides, the efficacy of efforts to control malaria in many tropical countries is diminishing. This trend, together with the projected consequences of climate change, may prove to exacerbate substantially the significance of malaria in the coming decades. In this article we introduce the use of an evolutionary modeling approach to simulate the adaptation of mosquitoes and parasites to the available pesticides and drugs. By coupling genetic algorithms with a dynamic malaria-epidemiological model, we derive a complex adaptive system capable of simulating adapting and evolving processes within both the mosquito and the parasite populations. This approach is used to analyze malaria management strategies appropriate to regions of higher and lower degrees of endemicity. The results suggest that adequate use of insecticides and drugs may reduce the occurrence of malaria in regions of low endemicity, although increased efforts would be necessary in the event of a climate change. However, our model indicates that in regions of high endemicity the use of insecticides and drugs may lead to an increase in incidence due to enhanced resistance development. Projected climate change, on the other hand, may lead to a limited reduction of the occurrence of malaria due to the presence of a higher percentage of immune persons in the older age class.     

Knowledge, beliefs, and practices in relation to malaria transmission and vector control in Guatemala

As part of an effort to involve community members in malaria control activities, we studied knowledge, beliefs, and practices of residents of both the Pacific coastal plain and northeastern Guatemala related to malaria transmission and Anopheles albimanus control. Most residents recognized the role of mosquitoes in malaria transmission, but few knew how mosquitoes acquired their infections or understood the risk of having an untreated person in their midst. If this were more widely known, residents might put greater pressure on infected patients to seek timely and appropriate antimalarial treatment. Seventy-three percent of families owned one or more bed nets; however, even though most informants believed that bed nets help protect against malaria, the major reason for using them was to prevent nuisance mosquito bites. It is concluded that efforts should be made to promote bed net use by seeking ways to make them more affordable and by emphasizing their effectiveness as a barrier to nuisance mosquitoes. Although residents have a very positive opinion of the National Malaria Service spray teams, it is proposed that cooperation might be improved if malaria workers would emphasize the fact that house spraying reduces the numbers of nuisance mosquitoes and other pest insects, rather than focusing solely on malaria prevention, which most informants believed was less important. This study emphasizes the importance of understanding community beliefs and practices when planning or evaluating vector control activities.     

Beliefs about worry and intrusions: the Meta-Cognitions Questionnaire and its correlates

In 1995 the World Health Assembly voted to launch a global program for the eradication of malaria. The program lasted fourteen years. Though it was successful in a number of countries, eradication failed in most of the developing world. Studies that have examined the failure of malaria eradication have focused on the various technical, organizational, and financial problems which hampered the program. While these critiques are valid, they lose sight of the wider political, economic and cultural context within which eradication was conceived and executed. Malaria eradication was a product of a postwar vision of economic and social development and needs to be examined in this context. Many of the problems that plagued eradication efforts flowed from this intense association between eradication and "development".     

The peripheral platelet count in response to intravenous infusion of isoprenaline

We studied the possible correlation of VH morbidity or HBsAg carrier rate with the prevalence of malaria and enteric among the 50 geographical regions of Greece. Malaria was considered as an index of mosquito density and enteric as an index of the local hygienic conditions. Morbidity data on the studied reportable diseases for the period 1954-73 and the HBsAg carrier rate (4-7%) among 17,991 recruits of the Greek Air Force, coming from all the geographical regions of Greece, were used. The statistical analysis of our data showed that VH morbidity (which is mainly hepatitis A) is significantly correlated with enteric morbidity, while HBsAg carrier rate with malaria. Our data support the significance of the role of mosquitoes in the spread of HB at least under the prevailing conditions in Greece.     

FDA device approval regulations

Recently, the trend in the number of people traveling from the tropics to malaria-free areas has tremendously increased and this is paralleled by the number of imported malaria cases. Imported infected mosquitoes transmitting the infection to persons living or working nearby international airports have been reported. The possibility that mosquitoes may also reach areas far away from the landing area in the baggage of international travelers is indicated by two cases that are reported here. Malaria should be investigated in any case of unexplained fever even if no apparent risk factor for imported malaria is present, regardless of the distance from international airports.     

The history of malaria in S? Tomé. Considerations on an epidemic

Using a historical approach of malaria control in the island of S?o Tomé, the author describes the evolution of strategies used with special reference to the last 25 years. From a zero mortality rate in children under 4 years in 1981/83, malaria became the first cause of morbidity and mortality after the epidemic of 1985/86. Malaria was introduced in 1493, when the virgin island was populated with individuals of various origins (Europe, Africa). The problem became more important as the population of S?o Tomé increased in the XIXth century, with immigration of workers for cultivation of coffee and cocoa. At that time, methods of control of "fevers" were already defined including drainage of swamps, cleansing of the environment and use of quinine for prophylaxis and treatment. At the beginning of the XXth century, with the first epidemiological investigations, global plans of medical assistance and free delivery of chloroquine were elaborated. Between 1946 and 1967, localities were stratified according to their endemicity, the major vectorial species (Anopheles gambiae sp.) were identified and the parasitological indices were calculated. All species of the malarial parasites coexisted, Plasmodium falciparum being the most prominent. In 1968, the Mission of Eradication of Malaria was created. Between 1977 and 1983, anti-vectorial control (indoor spraying, larvicides) resulted in a decrease of mortality rate. The interruption of the antivectorial control activities was responsible for the 1985/86 epidemic and the restoration of the levels of endemicity.     

Malaria surveillance -- United States, 1994

PROBLEM/CONDITION: Malaria is caused by infection with one of four species of Plasmodium (i.e., P. falciparum, P. vivax, P. ovale, and P. malariae ), which are transmitted by the bite of an infective female Anopheles sp. mosquito. Most malarial infections in the United States occur in persons who have traveled to areas (i.e., other countries) in which disease transmission is ongoing. However, cases are transmitted occasionally through exposure to infected blood products, by congenital transmission, or by local mosquitoborne transmission. Malaria surveillance is conducted to identify episodes of local transmission and to adapt prevention recommendations. REPORTING PERIOD COVERED: Cases with onset of symptoms during 1994. DESCRIPTION OF SYSTEM: Malaria cases confirmed by blood smear are reported to local and/or state health departments by health-care providers and/or laboratories. Case investigations are conducted by local and/or state health departments, and the reports are transmitted to CDC through the National Malaria Surveillance System (NMSS), which was the source of data for this report. Numbers of cases reported through NMSS may differ from those reported through other passive surveillance systems because of differences in the collection and transmission of data. RESULTS: CDC received reports of 1,014 cases of malaria with onset of symptoms during 1994 among persons in the United States or one of its territories. This number represented a 20% decrease from the 1,275 cases reported for 1993. P. vivax, P. falciparum, P. malariae, and P. ovale accounted for 44%, 44%, 4%, and 3% of cases, respectively. More than one species was present in five persons (<1% of the total number of patients). The infecting species was not determined in 50 (5%) cases. The number of reported malaria cases in U.S. military personnel decreased by 86% (i.e., from 278 cases in 1993 to 38 cases in 1994). Of the U.S. civilians who acquired malaria during travel to foreign countries, 18% had followed a chemoprophylactic drug regimen recommended by CDC for the area to which they had traveled. Five persons became infected while in the United States; the infection was transmitted to two of these persons through transfusion of infected blood products. The remaining three cases, which occurred in Houston, Texas, were probably locally acquired mosquitoborne infections. Four deaths were attributed to malaria. INTERPRETATION: The 20% decrease in the number of malaria cases from 1993 to 1994 resulted primarily from an 86% decrease in cases among U.S. military personnel after withdrawal from Somalia. Because most malaria cases acquired in Somalia during 1993 resulted from infection with P. vivax, there was a proportionately greater decrease during 1994 in the number of cases caused by P. vivax relative to those caused by P. falciparum. ACTIONS TAKEN: Additional information was obtained concerning the four fatal cases and the five cases acquired in the United States. Malaria prevention guidelines were updated and distributed to health-care providers. Persons traveling to a geographic area in which malaria is endemic should take the recommended chemoprophylactic regimen and should use protective measures to prevent mosquito bites. Persons who have a fever or influenza-like illness after returning from a malarious area should seek medical care; medical evaluation should include a blood smear examination for malaria. Malarial infections can be fatal if not promptly diagnosed and treated. Recommendations concerning prevention and treatment of malaria can be obtained from CDC.     

Epidemiological features of severe paediatric malaria in north western Ethiopia

Malaria remains a major public health challenge in sub-Saharan Africa, yet our knowledge of the epidemiology of malaria in terms of patterns of mortality and morbidity is limited. To examine the clinical and epidemiological presentation of severe life-threatening malaria in Humera, north western Ethiopia studies were conducted among the childhood population in the community, those presenting to out-patient facilities and those admitted to the district hospital. The overall P. falciparum parasite rate among children aged 0-9 years resident within the area was only 12% confirming the low level of endemicity in this area. P. vivax infections were present in 5% of children. Between July 1993 and June 1994 peak out-patient presentation with Plasmodium falciparum coincided with the rains with over 50% of cases occurring between August and October whilst P. vivax infections were predominant during the hot, dry months. Malaria was an important cause of paediatric admission to the local district hospital with an estimated 4.7% of the at-risk childhood community warranting intensive clinical management each year. Case fatality rates were high and the clinical spectrum of severe disease indicated a preponderance of cerebral malaria cases. In addition, respiratory distress was a feature in 12% of the malaria admissions. The suggestion that the coexistence of Plasmodium falciparum and Plasmodium vivax may serve to reduce the severe clinical consequences of P. falciparum malaria is not supported by these observations.     

Thrombophlebitis of the jugular vein: a correlation between echography and computed tomography with angiography. A case report]

A rapid immunodiagnostic test (ICT Malaria PfTest) has been developed by ICT Diagnostics (Sydney, Australia) for the diagnosis of Plasmodium falciparum infection. The test is an antigen capture assay based on the detection of P. falciparum histidine-rich protein 2 in peripheral blood. This study was undertaken to assess the performance and usefulness of the test as a diagnostic method in highly malarious, inaccessible forested villages of Mandla district, central India. In all, 353 patients with fever were scanned by the test in parallel with thick blood film examination. The sensitivity and specificity were 100% and 84.5%, respectively. The whole test took about 5 min. The test results became negative in most cases (70%) within 7 d after initiation of curative chemotherapy. The test is simple, easy to learn and accurate, and may prove to be an important tool in the battle against falciparum malaria.     

Antimalarial activity of synthetic analogues of distamycin

Malaria, one of the most serious diseases transmitted by arthropods, is largely present in tropical and even temperate zones in endemic or epidemic form. More than 40% of the world's population lives in areas at risk for exposure, and the World Health Organization reports that approximately 300 million people are affected by the infection (mostly caused by the species Plasmodium falciparum), with 1-2 million deaths per year. These data, and the fact that malaria is becoming increasingly refractory to treatment through resistance of the parasite to antimalarial agents currently in use, e.g., chloroquine, emphasize the need to develop new drugs. The well-known antiparasitic activity of oligopyrrolamidine natural products, such as distamycin and netropsin, suggested the antimalarial evaluation of related compounds obtained by new chemical modifications. Besides possessing antiviral and antitumoural properties, distamycin exhibits interesting in vitro activity against P. falciparum. Unfortunately, the high toxicity associated with this product precludes its development as a drug. However, some synthetic analogues of distamycin proved to be highly active against chloroquine-sensitive and -resistant strains of P. falciparum, besides showing low toxicity in vitro.     

Oxidative stress in malaria; implications for prevention and therapy

Malaria affects world-wide more than 200 million people, of which 1-2 million die every year. New drugs and treatment strategies are needed to face the rapidly increasing problems of drug resistance. During a malaria infection, both host and parasite are under oxidative stress. Increased production levels of reactive oxygen species (ROS, e.g superoxide anion and the hydroxyl radical) are produced by activated neutrophils in the host and during degradation of haemoglobin in the parasite. The effects of ROS in malaria can be both beneficial and pathological, depending on the amount and place of production. Enhanced ROS production after the administration of pro-oxidants, which is directed against the intra-erythrocytic parasite, inhibits the infection both in vitro and in vivo. However, ROS are also involved in pathological changes in host tissue like damage of the vascular endothelial lining during a malaria infection (cerebral malaria). Pro-oxidants support the host defense against the parasite when working in or near the infected cell but potentially cause vascular damage when working on or near the vascular lining. Examples of pro-oxidants are found among xenobiotics and food components. Important new drugs belonging to the class of pro-oxidants are artemisinin and its derivatives. Anti-oxidants potentially counteract these agents. Treatment with anti-oxidants or chelators of metals to prevent their catalytic function in the generation of ROS may prevent vascular pathology. In addition, the iron chelator desferrioxamine, exhibits an antiparasitic activity, because iron is also essential for the proliferation of the parasite. Cytokines play an important role in ROS-related pathology of malaria, though their mechanism of action is not completely elucidated. This field might bring up new treatment concepts and drugs. Drugs which prevent host pathology, such as the cerebral complications might be life saving.     

Acute mediastinitis due to esophageal perforation--a case report

Malaria is responsible for nearly 500 million clinical cases per year, only a small proportion of whom will become severely ill. Socioeconomic risk factors may play a role in the development of severe malaria in African children and in their susceptibility to reinfection. In Gabon, 100 children suffering from severe malaria, defined as hyperparasitaemia and/or severe anaemia, were matched for sex, age and provenance to 100 children with mild malaria. Socioeconomic factors were assessed using a standard questionnaire and compared between the 2 groups. The children were followed-up and the time to first reinfection was recorded. No significant influence of socioeconomic factors could be detected on the severity of disease or the time to first reinfection. Socioeconomic factors are not major determinants of severe malarial anaemia and hyperparasitaemia in children in Gabon.     

Counseling the international traveler. Update '93

The itinerary of international travelers will largely determine the amount of pretravel counseling, number of immunizations and type of malaria prophylaxis they will need. The countries visited are also the best predictor of traveler's diarrhea. Only yellow fever and cholera vaccines are required for entry into certain countries; the latter generally given only to satisfy entry requirements. Polio vaccine is important for some areas and is frequently neglected. For most malarious areas, chloroquine once per week is recommended. Mefloquine should be prescribed weekly for travelers going to chloroquine resistant malarious areas. Traveler's diarrhea is best prevented by avoiding high risk foods and beverages. Antibiotics, generally not recommended for prophylaxis, are very effective in treatment. Travelers should be reminded to advise physicians of their travel history during future medical encounters so that otherwise exotic tropical diseases, possibly contracted during travel, may be considered in diagnoses.     

'No other logical choice': global malaria eradication and the politics of international health in the post-war era

In 1955 the Eighth World Health Assembly voted to initiate a program for the global eradication of malaria. The global eradication of malaria represented a remarkable leap of faith. Many health authorities, both within and outside the Assembly, viewed eradication as at best fool hardy, and at worst, potentially disastrous. To understand why the World Health Assembly went ahead with a Global Eradication strategy, despite these concerns, it is necessary to examine the politics of international health and development in the post-war era. This political context shaped decisions about the adoption of DDT as a primary tool in the fight against malaria, as well as the adoption of the Malaria Eradication Program. It is equally important to understand how the advocates of an eradication strategy shaped arguments and developed support for their cause in the years leading up to the Eighth World Health Assembly meeting.     

The effect of short-term fasting, apolipoprotein E gene polymorphism, and sex on plasma lipids

Until today, malaria is still one of the most important diseases in Malaysia. This is because Malaysia is located within the equatorial zone with high temperatures and humidities, usually important for the transmission of malaria. The number of malaria cases were estimated to be around 300,000 before the launching of the Malaria Eradication Program (MEP). The program was successful in reducing the numbers progressively during the 1967-1982 period. During the period 1980-1991, the highest number of malaria cases recorded for the country was 65,283 in 1989 (16,902 in Peninsular Malaysia, 47,545 in Sabah and 836 in Sarawak) whilst the lowest was 22,218 (10,069 in Peninsular Malaysia, 11,290 in Sabah and 859 in Sarawak) in 1983. In Malaysia, there are 434 species of mosquitos, representing 20 genera. Of these, 75 species are Anopheles that comprise of 2 subgenus, i.e. Anopheles and Cellia. Of the 75 species, only 9 have been reported as vectors: An. maculatus, An balabacensis, An. dirus, An. letifer An. campestris, An. sundaicus, An. donaldi, An. leucophyrus and An. flavirostris. The behavior, seasonal abundance, biting activities and breeding sites of these species are discussed.     

Glucose-6-phosphate dehydrogenase deficiency and malaria

Glucose-6-phosphate dehydrogenase (G6PD) is a cytoplasmic enzyme that is essential for a cell's capacity to withstand oxidant stress. G6PD deficiency is the commonest enzymopathy of humans, affecting over 400 million persons worldwide. The geographical correlation of its distribution with the historical endemicity of malaria suggests that 66PD deficiency has risen in frequency through natural selection by malaria. This is supported by data from in vitro studies that demonstrate impaired growth of P. falciparum parasites in G6PD-deficient erythrocytes. Attempts to confirm that G6PD deficiency is protective in field studies of malaria have yielded conflicting results, but recent results from large case control studies conducted in East and West Africa provide strong evidence that the most common African G6PD deficiency variant, G6PD A-, is associated with a significant reduction in the risk of severe malaria for both G6PD female heterozygotes and male hemizygotes. The effect of female homozygotes on severe malaria remains unclear but can probably be assumed to be similar to that of comparably deficient male hemizygotes.     

A nestable fiber pot for sampling resting mosquitoes

To enhance the effectiveness of an arbovirus monitoring program, we evaluated a commercially available device for sampling resting vector mosquitoes. Diverse Anopheles, Culiseta, and Culex mosquitoes were taken in these nestable fiber pots. The pots sample about as many Culiseta melanura mosquitoes per device as do conventional resting boxes, but fewer than do boxes fitted with expanded frames. More Cs. melanura, and more bloodfed mosquitoes, but fewer species of mosquitoes are harvested with fiber pots than with CDC light traps. Fiber pots are more readily used, transported, and stored and are less expensive than conventional resting box devices or CDC light traps. A monitoring program based on the use of fiber pots, therefore, expends fewer resources than one using conventional resting boxes and collects about as many vector mosquitoes.