Kamini Mendis - Academia.edu (original) (raw)

Papers by Kamini Mendis

The American Journal of Tropical Medicine and Hygiene

ABSTRACT. International travel, a major risk factor for imported malaria, has emerged as an impor... more ABSTRACT. International travel, a major risk factor for imported malaria, has emerged as an important challenge in sustaining malaria elimination and prevention of its reestablishment. To make travel and trade safe, the WHO adopted the International Health Regulations (IHR) which provides a legal framework for the prevention, detection, and containment of public health risks at source. We conducted a systematic review to assess the relevance and the extent of implementation of IHR practices that can play a role in reducing malaria transmission. Selected studies addressed control, elimination, and prevention of reestablishment of malaria. Study themes focused on appraisal of surveillance and response, updating national policies to facilitate malaria control and elimination, travel as a risk factor for malaria and risk mitigation methods, vector control, transfusion malaria, competing interests, malaria in border areas, and other challenges posed by emerging communicable diseases on m...

Malaria Journal

Background Malaria was endemic in Sri Lanka for centuries and was eliminated in 2012. It is widel... more Background Malaria was endemic in Sri Lanka for centuries and was eliminated in 2012. It is widely assumed that the costs of elimination are generally greater than that of control. The costs of malaria elimination in Sri Lanka with that of malaria control in the past using periods in which starting transmission dynamics were similar were compared. Methods The expenditure of the Anti-Malaria Campaign (AMC), total and by budget category, during 2002–2010 is compared with that of malaria control during the period 1980–1989, using regression analyses and the Mann Whitney U statistic. Results The expenditure on malaria control and malaria elimination was similar ranging from 21 to 45 million USD per year when adjusted for inflation. In both periods, external funding for the malaria progamme constituted around 24% of the total budget; during the control phase in the 1980s, external funds came from bilateral agencies and were disbursed in accordance with government budget guidelines. In th...

Malaria Journal, 2020

Background Following malaria elimination, Sri Lanka was free from indigenous transmission for six... more Background Following malaria elimination, Sri Lanka was free from indigenous transmission for six consecutive years, until the first introduced case was reported in December 2018. The source of transmission (index case) was a member of a group of 32 migrant workers from India and the location of transmission was their residence reporting a high prevalence of the primary vector for malaria. Despite extensive vector control the situation was highly susceptible to onward transmission if another of the group developed malaria. Therefore, Mass Radical Treatment (MRT) of the group of workers for Plasmodium vivax malaria was undertaken to mitigate this risk. Method The workers were screened for malaria by microscopy and RDT, their haemoglobin level assessed, and tested for Glucose 6 phosphate dehydrogenase deficiency (G6PD) using the Care Start RDT and Brewers test prior to treatment with chloroquine (CQ) 25 mg/kg body weight (over three days) and primaquine (PQ) (0.25 mg/kg/day bodyweight...

Pathogens and Global Health, 2021

ABSTRACT Sri Lanka reported the last case of indigenous malaria in October 2012, and received mal... more ABSTRACT Sri Lanka reported the last case of indigenous malaria in October 2012, and received malaria-free certification from WHO in September 2016. Malaria cases have since, shifted from indigenous to imported, and the country remains receptive and vulnerable to malaria. A case-based epidemiological study was conducted on all imported malaria cases reported in the country in 2015 and 2016 with the aim of profiling imported malaria to improve the effectiveness of the surveillance and case management system for malaria. Data were obtained from case reports of the Anti Malaria Campaign, hospital records and laboratory registers. Over the 2 years, 77 imported malaria infections were diagnosed in 54 Sri Lankans and 23 foreign nationals. A majority of the infections were reported among males (93%) in the age group of 21–50 years (85.8%), and all were recent travelers overseas. Most patients were detected by passive case detection, but 10% of cases were detected by Active Case Detection. Only 25% of patients were diagnosed within 3 days of the onset of symptoms. In 32% of patients, the diagnosis was delayed by more than 10 days after the onset of symptoms. Plasmodium falciparum infections manifested significantly earlier after arrival in Sri Lanka than did P.vivax infections. The majority of patients (74%) were diagnosed in the Western Province, which was not endemic for malaria. A third of patients were diagnosed in the private sector. The shift in the epidemiology of malaria infection from before to after elimination has implications for preventing the reestablishment of malaria.

Additional file 6: Fig. S5. Phylogenetic analysis of the msp3Îą gene. The maximum-likelihood tree... more Additional file 6: Fig. S5. Phylogenetic analysis of the msp3Îą gene. The maximum-likelihood tree was constructed based on the general time-reversible model with gamma distribution by using case sequences and those retrieved from GenBank (1440 bp). The case sequences are highlighted in red, whereas the sequence obtained for the positive control is highlighted in blue. Figures on branches are bootstrap values. Only bootstrap values more than 70% are shown on the nodes.

Additional file 3: Fig. S2. Phylogenetic analysis of the msp1 gene (F1). The maximum-likelihood t... more Additional file 3: Fig. S2. Phylogenetic analysis of the msp1 gene (F1). The maximum-likelihood tree was constructed based on the general time-reversible model with gamma distribution by using case sequences and those retrieved from GenBank (1178 bp). The case sequences are highlighted in red, whereas the sequence obtained for the positive control is highlighted in blue. Figures on branches are bootstrap values. Only bootstrap values more than 70% are shown on the nodes.

Journal of Vector Borne Diseases, 2021

Trends in Parasitology, 2020

Plasmodium vivax is an important cause of malaria, associated with a significant public health bu... more Plasmodium vivax is an important cause of malaria, associated with a significant public health burden. Whilst enhanced malaria-control activities have successfully reduced the incidence of Plasmodium falciparum malaria in many areas, there has been a consistent increase in the proportion of malaria due to P. vivax in regions where both parasites coexist. This article reviews the epidemiology and biology of P. vivax, how the parasite differs from P. falciparum, and the key features that render it more difficult to control and eliminate. Since transmission of the parasite is driven largely by relapses from dormant liver stages, its timely elimination will require widespread access to safe and effective radical cure. Extent and Burden of Plasmodium vivax Of the five Plasmodium species that cause human malaria, Plasmodium vivax is the most geographically widespread. The parasite is capable of surviving quiescent for prolonged periods when conditions are not conducive to its ongoing transmission. A century ago P. vivax was prevalent in almost all countries; even though the vivax endemic world has shrunk considerably, over four billion people remain at risk of infection [1]. In 2017, transmission was reported from 49 countries across Central and South America, the Horn of Africa, Asia, and the Pacific islands (Figure 1). In almost two-thirds of coendemic countries P. vivax is the predominant species of malaria (Figure 2), the proportion of malaria attributable to the parasite being greatest in areas where the prevalence of malaria is low (Figure 3) [2,3]. Until recently the global burden of P. vivax malaria was derived from estimates of P. falciparum, the most prevalent species causing human malaria. However, a growing awareness of the public health importance of P. vivax has led to the strengthening of surveillance systems and better reporting practices of all of the Plasmodium species. The World Health Organization (WHO) first included P. vivax case estimates in its World Malaria Report (WMR) in 2013, documenting between 11.9 and 22 million P. vivax clinical cases per year [4]. Recent estimates, incorporating national surveillance data, prevalence surveys, and geospatial mapping, have revised the global burden to between 13.7 and 15 million cases in 2017 [1]. An estimated 82% (11.7 million cases) of the global vivax burden comes from four high-burden countries: India, Pakistan, Ethiopia, and Sudan. In sub-Saharan Africa, where the burden of malaria is overwhelmingly attributable to P. falciparum (Figure 1), the low prevalence of P. vivax is attributed to a high proportion of the population having a Duffy-negative blood group. The Duffy antigen is an important molecule for the erythrocytic invasion of P. vivax, and the lack of the receptor on red blood cells reduces the risk of infection [5]. However, a recent review of clinical and vector data has shown that P. vivax is present across almost all malaria-endemic regions of Africa [6]. Biological Differences between P. falciparum and P. vivax The control and elimination of P. vivax is more challenging than that of P. falciparum, a reflection of key differences in parasite and vector biology. P. vivax usually circulates at low peripheral parasite Highlights Plasmodium vivax infection is present across most of the malaria-endemic world. P. vivax relapses, arising from dormant liver stages, cause recurrent episodes of malaria that are the main determinant of significant morbidity, mortality, and ongoing transmission.

Infection and Immunity, 1998

A successful anti-blood stage malaria vaccine trial based on a leading vaccine candidate, the maj... more A successful anti-blood stage malaria vaccine trial based on a leading vaccine candidate, the major merozoite surface antigen-1 (MSP1), is reported here. The trial was based on Plasmodium cynomolgi , which is a primate malaria parasite which is highly analogous to the human parasite Plasmodium vivax , in its natural host, the toque monkey, Macaca sinica . Two recombinant baculovirus-expressed P. cynomolgi MSP1 proteins, which are analogous to the 42- and 19-kDa C-terminal fragments of P. falciparum MSP1, were tested by immunizing three groups of three animals each with either p42, p19, or both together. The vaccines were delivered subcutaneously in three doses at 4-week intervals with complete and incomplete Freund’s adjuvants. Very high antibody titers were obtained against both vaccinating antigens as measured by enzyme-linked immunosorbent assay (10 6 and above) and against whole parasites as measured by indirect immunofluorescence assay (>10 5 ), achieving, in most animals, a...

Journal of Vector Borne Diseases, 2019

The American Journal of Tropical Medicine and Hygiene, 2001

We estimate that the global burden of malaria due to Plasmodium vivax is ϳ70-80 million cases ann... more We estimate that the global burden of malaria due to Plasmodium vivax is ϳ70-80 million cases annually. Probably ϳ10-20% of the world's cases of P. vivax infection occur in Africa, south of the Sahara. In eastern and southern Africa, P. vivax represents around 10% of malaria cases but Ͻ 1% of cases in western and central Africa. Outside of African, P. vivax accounts for Ͼ 50% of all malaria cases. About 80-90% of P. vivax outside of Africa occurs in the Middle East, Asia, and the Western Pacific, mainly in the most tropical regions, and 10-15% in Central and South America. Because malaria transmission rates are low in most regions where P. vivax is prevalent, the human populations affected achieve little immunity to this parasite; as a result, in these regions, P. vivax infections affect people of all ages. Although the effects of repeated attacks of P. vivax through childhood and adult life are only rarely directly lethal, they can have major deleterious effects on personal well-being, growth, and development, and on the economic performance at the individual, family, community, and national levels. Features of the transmission biology of P. vivax give this species greater resilience than the less robust Plasmodium falciparum in the face of conditions adverse to the transmission of the parasites. Therefore, as control measures become more effective, the residual malaria burden is likely increasingly to become that of P. vivax.

Parassitologia, 1991

During natural infections of P. vivax malaria a variety of immune responses to the infection affe... more During natural infections of P. vivax malaria a variety of immune responses to the infection affect infectivity of the parasites to mosquitoes. Sexual stage antigens present in the blood stage parasites induce antibodies which may either enhance or suppress the infectivity of the sexual parasites to mosquitoes. Subsequent infections of P. vivax do not, unless occurring within less than 4 months, boost this response indicating a very short immune memory for the relevant antigens. Blood infection also results in the release of cytokines and other non-antibody factors which together can mediate death of the blood stage sexual parasites. These factors are associated with paroxysm in non-immune individuals. In individuals from an endemic area with age-acquired anti-disease immunity clinical symptoms are mild and the parasite killing factors are not induced.

Proceedings of the National Academy of Sciences, 1993

The goal of this work is to develop a method for the functional analysis of malaria genes using t... more The goal of this work is to develop a method for the functional analysis of malaria genes using the method of DNA transfection. We have developed a transient transfection vector by constructing a chimeric gene in which the firefly luciferase gene was inserted in frame into the coding region of the pgs28 gene of Plasmodium gallinaceum. This plasmid DNA was introduced into P. gallinaceum gametes and fertilized zygotes by electroporation, and luciferase expression was assayed after 24 hr. This report of successful introduction and expression of a foreign gene in a malaria parasite demonstrates the feasibility of this approach to developing methods for the functional analysis of parasite genes.

European Journal of Immunology, 1990

Human Tcell proliferative responses, of 33 adult Sri Lankans convalescing from Plasmodium vivax i... more Human Tcell proliferative responses, of 33 adult Sri Lankans convalescing from Plasmodium vivax infections, to several I? v i v a antigens (i.e. a soluble extract of asexual erythrocytic stage parasites and two cloned antigens that are potential vaccine candidates PV200 and GAM-1) were assessed. The peripheral blood mononuclear cell proliferative responses to the soluble extract of I? vivax, as assessed by studying both the proportion of responders and the degree of the response, were significantly lower in a group of individuals resident in a malaria endemic area in Sri Lanka than in another group that did not have a lifelong exposure to malaria but had acquired the disease on a visit to an endemic region. Individuals of both groups responded equally well to mitogen.The responses to a non-malarial antigen such as purified protein derivative of tuberculin were only marginally lower in residents of the malaria-endemic region. These findings suggest that exposure to endemic I? vivax malaria leads to a specific immunosuppression to I? vivax antigens. Immunosuppression of a much lower degree was evident to a non-malarial antigen. * This investigation received support from the UNDPMrorld B a n W H O Special Programme for Research and Training in Tropical Diseases.

Annals of Tropical Medicine & Parasitology, 2005

Although the ABO blood group of the human host has been reported to influence malarial infection,... more Although the ABO blood group of the human host has been reported to influence malarial infection, there have been few clinical observations on this effect. A hospital-based, comparative study was therefore performed to investigate the relationship between blood-group type and severe disease in Plasmodium falciparum malaria. Overall, 243 cases of malaria (163 uncomplicated and 80 severe) and 65 patients with severe, non-malarial infections were studied. In terms of ABO-blood-group composition, the patients with severe malaria were significantly different from the patients with the uncomplicated disease (P,0.001) and also from a population control described previously (P,0.0001). The patients with uncomplicated malaria or severe but non-malarial disease were, however, similar to the population control. The cases of severe malaria were significantly less likely to be of blood group O (P50.0003), and significantly more likely to be of group AB (P,0.0001), than the patients with nonsevere malaria. It appears that individuals who are of blood-group O are relatively resistant to the severe disease caused by P. falciparum infection.

Transactions of the Royal Society of Tropical Medicine and Hygiene, 2003

In a cross-sectional study, carried out in January 1997 at the beginning of the school year, the ... more In a cross-sectional study, carried out in January 1997 at the beginning of the school year, the impact of repeated attacks of malarial infection on the cognitive performance of children at school entry in moderate malaria-endemic areas of Sri Lanka was investigated. The cognitive performance of 325 schoolchildren in grade 1 (mostly aged 5-6 years) in 2 districts of Sri Lanka which are endemic for malaria (Anuradhapura and Moneragala) was assessed by an entry performance test developed by the National Institute of Education, Sri Lanka. The indices assessed included writing, language and mathematical skills. There was no difference in any of the cognitive performance indices between children from Anuradhapura and Moneragala districts. The scores of most of the indices decreased as the number of malaria infections experienced by a child increased and the ability to identify letters was significantly impaired by the number of malaria infections a child had experienced after controlling for socioeconomic and nutritional status. These findings suggest that repeated attacks of malaria in children can have an adverse impact on their development.

Additional file 2: Fig. S1. Phylogenetic analysis of the csp gene. The maximum-likelihood tree wa... more Additional file 2: Fig. S1. Phylogenetic analysis of the csp gene. The maximum-likelihood tree was constructed based on the general time-reversible model with gamma distribution by using case sequences and those retrieved from GenBank (848 bp). The case sequences are highlighted in red, whereas the sequence obtained for the positive control is highlighted in blue. Figures on branches are bootstrap values. Only bootstrap values more than 70% are shown on the nodes.

Nature, 1964

The invaluable support provided by Ms Mar Velarde, ISGlobal, Malaria Eradication Scientific Allia... more The invaluable support provided by Ms Mar Velarde, ISGlobal, Malaria Eradication Scientific Alliance, in the desk review for the drafting committee is gratefully acknowledged. The contributions of all members of the drafting committee are recognized. Their precision, careful attention and timely, precious feedback were instrumental for completion of the work. The external survey was ably managed by Mr Ryan Williams, WHO Global Malaria Programme, following the indications of the drafting committee, and all inputs and the analysis of the survey results were efficiently compiled by Ms Silvia Schwarte, WHO Global Malaria Programme. The inputs received from over 20 institutions and groups are greatly appreciated. These included the Asia-Pacific Malaria Elimination Network; the Foundation for Innovative New Diagnostics; the Gates Foundation malaria programme; IVCC