Symptomless Plasmodium vivax parasitemias and malaria eradication in Santa Catarina State, Brazil

Jones, S. Avery; Neto, J. A. Ferreira

doi:10.1590/s0037-86821971000100003

Cited by 5 publications

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“…Symptomless infections by P. vivax also have not been described in Brazil, except in southern coastal areas, where symptomless or oligosymptomatic infections by P. vivax have been reported. 31 However, in these areas, even symptomatic malaria is quite atypical, and the possibility has not been excluded that this regional malaria may be caused by a variant of P. vivax or P. vivax-like parasite.…”

Section: Discussionmentioning

confidence: 99%

High prevalence of asymptomatic Plasmodium vivax and Plasmodium falciparum infections in native Amazonian populations.

Alves¹,

Durlacher²,

Menezes³

et al. 2002

The American Journal of Tropical Medicine and Hygiene

264

215

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Abstract. The epidemiology of malaria in 2 riverine localities in Rondônia, Brazilian western Amazônia, was assessed by a 1-year study at Portuchuelo, and a cross-sectional survey at riverine communities at Rio Machado ‫ס(‬ Ji-Paraná). Plasmodium spp. infections were diagnosed by light microscopy and by polymerase chain reaction (PCR) amplification of ribosomal DNA. PCR was 6-7 times more efficient than microscopy for detecting plasmodial infections. Both Plasmodium vivax and Plasmodium falciparum infections occurred as asymptomatic and symptomatic forms of the disease. The relation between symptomatic and asymptomatic clinical forms was roughly similar for both species of Plasmodium. Symptomless patients were monitored for 2 months. The prevalence of symptomless infections was 4-5 times higher than the symptomatic ones-respectively, 20% and 4.6% for Portuchuelo and 49.5% and 10% for JiParaná. Symptomatic malaria occurred mostly in patients in younger age groups. In contrast, there was a significant association of symptomless malaria with older age groups (medians of 26.5 and 21 years, respectively, for Portuchuelo and Ji-Paraná), whereas the age medians for symptomatic malaria were 14 and 8 years, respectively, in the 2 regions. Symptomatic malaria also was more prevalent in groups living for shorter times in Amazônia (13 and 4 years, respectively, for Portuchuelo and Ji-Paraná) as compared with symptomless malaria, which was more prevalent in groups living for longer periods in the region (medians of 25.5 and 18 years, respectively, for Portuchuelo and Ji-Paraná). The high prevalence of symptomless malaria may pose new problems for the currently adopted strategy for the control of malaria in the Amazonian region, which is essentially based on the treatment of symptomatic patients.

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Section: Discussionmentioning

confidence: 99%

High prevalence of asymptomatic Plasmodium vivax and Plasmodium falciparum infections in native Amazonian populations.

Alves¹,

Durlacher²,

Menezes³

et al. 2002

The American Journal of Tropical Medicine and Hygiene

264

215

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“…Other studies carried out in Brazil (Jones & Neto 1971Prata et al 1988, Andrade 2001a,b, Pithan et al 2002, Scopel et al 2005 and in other Latin American countries (Gonzalez 1997, Pérez 1998, Laserson et al 1999, Suárez-Mutis et al 2000a,b, Roper et al 2000, Roshnavaran et al 2003, Branch et al 2005 were important for the global comprehension of the problem.…”

Section: Chronicity and Asymptomatic Infectionmentioning

confidence: 95%

“…P. vivax was found in 74.7% of the infections, P. falciparum in 26.6%, including mixed infection in 1.6%, and P. malariae in 0.3%. IgG antibodies for P. vivax and P. falciparum were detected by indirect immunofluorescence in 83.2 and 71.7%, respectively, but the geometrical means of the assays were low (72.5 and 54.6), thus characterizing unstable transmission.Other studies carried out in Brazil (Jones & Neto 1971Prata et al 1988, Andrade 2001a,b, Pithan et al 2002, Scopel et al 2005 and in other Latin American countries (Gonzalez 1997, Pérez 1998, Laserson et al 1999, Suárez-Mutis et al 2000a,b, Roper et al 2000, Roshnavaran et al 2003, Branch et al 2005 were important for the global comprehension of the problem. …”

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confidence: 95%

A new challenge for malaria control in Brazil: asymptomatic Plasmodium infection - a review

Coura

Suárez-Mútis

Ladeia‐Andrade

2006

Mem. Inst. Oswaldo Cruz

151

141

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The evolution of malaria in Brazil, its morbidity, the malaria control programs, and the new challenges for these programs in the light of the emergence of asymptomatic infection in the Amazon region of Brazil were reviewed. Rondônia and, in our group, in If a mean of 25% is taken for the asymptomatic infection caused by Plasmodium sp. in the Amazon region of Brazil, malaria control will be difficult to achieve in that region with the measures currently utilized for such control. At least six Brazilian research groups have demonstrated that asymptomatic infection by Plasmodium is an important impediment to malaria control, among mineral prospectors in Mato Grosso and riverside communities in Key words: malaria -asymptomatic infection -control -Brazilian AmazonMalaria is the most widespread and most serious parasitic disease in the world. Forty percent of the world's population (2.4 billion people) is exposed to the infection, especially people who live in tropical and subtropical countries. In these regions, between 300 and 500 million cases are diagnosed every year, causing 1.5 to 2.7 million deaths per year, mostly among African children (WHO 2002). In 2001, according to a review by Hay et al. (2004), the overall incidence of malaria in the areas at risk in the world was 396 million cases, of which more than 80% were on the African continent, leading to the death of 1,123,000 cases, mostly children (Hay et al. 2004).In the Americas and in the Caribbean, 38% of the population (308 million people), in 21 countries, live in areas with malaria transmission, with a mean of 1.3 million cases per year. Thirty-six percent of these are in Brazil (OPS 1997, 1998, WHO 2002.Since 1970, when just over 52,000 cases were recorded in Brazil, malaria has gradually been increasing in this country. In the 1990s, the number of cases surpassed 500,000. In 1999, there were 610,000 notified cases of malaria in Brazil, and 99% of them were in the Amazon region (Ministério da Saúde 2003). Taking into account possible underreporting and cases of asymptomatic infection , Alves et al. 2002, Suárez-Mutis et al. 2004, Ladeia-Andrade 2005, it may be considered that more than 600,000 cases are occurring in Brazil every year (personal estimation). The number of cases of malaria re- show the areas at risk (Fig. 1) and the number of malaria cases notified in Brazil from 1970 to 2005 (Fig. 2).The course followed by malaria usually takes the form of a feverish acute systemic disease. The severity of the disease varies according to the parasite species (Plasmodium falciparum, P. vivax, P. malariae, and P. ovale; the last of these is not found in Brazil), the inoculum, the strain of the parasite, and the degree of previous immunity. Since the time of Hippocrates (460-377 BC), cases of infection of greater or lesser severity have been known. In 1900, Robert Koch first recognized cases of asymptomatic Plasmodium infection among patients in Papua New Guinea (Harrison 1978). This characteristic of malaria has been of concern for some time, particula...

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“…Symptomless malaria is commonly observed in high transmission areas in Africa and Southeast Asia, where transmission is very intense along the year and therefore individuals are continuously exposed to the parasite 7,9,17 . Although asymptomatic infections were described in the southern Brazilian State of Santa Catarina in 1971 caused by P. vivax, only in 1995 the first cases from the Brazilian Amazon, were reported among gold miners 2,15 . Recently, cases of healthy individuals infected with P. vivax and/or P. falciparum were reported in Rondônia, in the Amazon River basin and it was shown that autochthonous population, and not migrants, was responsible for the permanent endemicity of malaria in the area 1,10 .…”

Section: Introductionmentioning

confidence: 99%

Cross sectional study reveals a high percentage of asymptomatic Plasmodium vivax infection in the Amazon Rio Negro area, Brazil

Suárez-Mútis¹,

Cuervo²,

Leoratti

et al. 2007

Rev. Inst. Med. trop. S. Paulo

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SUMMARYA parasitological, clinical, serological and molecular cross-sectional study carried out in a highly endemic malaria area of Rio Negro in the Amazon State, Brazil, revealed a high prevalence of asymptomatic Plasmodium vivax infection. A total of 109 persons from 25 families were studied in five villages. Ninety-nine inhabitants (90.8%) had at least one previous episode of malaria. Serology showed 85.7% and 46.9% of positivity when P. falciparum antigens and P. vivax MSP-1, respectively, were used. Twenty blood samples were PCR positive for P. vivax (20.4%) and no P. falciparum infection was evidenced by this technique. No individual presenting positive PCR reaction had clinical malaria during the survey neither in the six months before nor after, confirming that they were cases of asymptomatic infection. Only one 12 year old girl presented a positive thick blood smear for P. vivax. This is the first description of asymptomatic Plasmodium infection in this area studied.

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Symptomless Plasmodium vivax parasitemias and malaria eradication in Santa Catarina State, Brazil

Cited by 5 publications

References 0 publications

High prevalence of asymptomatic Plasmodium vivax and Plasmodium falciparum infections in native Amazonian populations.

High prevalence of asymptomatic Plasmodium vivax and Plasmodium falciparum infections in native Amazonian populations.

A new challenge for malaria control in Brazil: asymptomatic Plasmodium infection - a review

Cross sectional study reveals a high percentage of asymptomatic Plasmodium vivax infection in the Amazon Rio Negro area, Brazil

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