Resistance to Pyrethroids in the Malaria Vector Anopheles albimanus in Two Important Villages in the Soconusco Region of Chiapas, Mexico, 2022.

Chiapas State comprises the largest malaria foci from Mexico, and 57% of the autochthonous cases in 2021, all with Plasmodium vivax infections, were reported in this State. Southern Chiapas is at constant risk of cases imported due to migratory human flow. Since chemical control of vector mosquitoes is the main entomological action implemented for the prevention and control of vector-borne diseases, this work aimed to investigate the susceptibility of Anopheles albimanus to insecticides. To this end, mosquitoes were collected in cattle in two villages in southern Chiapas in July-August 2022. Two methods were used to evaluate the susceptibility: the WHO tube bioassay and the CDC bottle bioassay. For the latter, diagnostic concentrations were calculated. The enzymatic resistance mechanisms were also analyzed. CDC diagnostic concentrations were obtained; 0.7 µg/mL deltamethrin, 12 µg/mL permethrin, 14.4 µg/mL malathion, and 2 µg/mL chlorpyrifos. Mosquitoes from Cosalapa and La Victoria were susceptible to organophosphates and to bendiocarb, but resistant to pyrethroids, with mortalities between 89% and 70% (WHO), and 88% and 78% (CDC), for deltamethrin and permethrin, respectively. High esterase levels are suggested as the resistance mechanism involved in the metabolism of pyrethroids in mosquitoes from both villages. Mosquitoes from La Victoria might also involve cytochrome P450. Therefore, organophosphates and carbamates are suggested to currently control An. albimanus. Its use might reduce the frequency of resistance genes to pyrethroids and vector abundance and may impede the transmission of malaria parasites.

Changing transmission dynamics among migrant, indigenous and mining populations in a malaria hotspot in Northern Brazil: 2016 to 2020.

BACKGROUND: Roraima state is the northernmost state in Brazil and the primary border-crossing point between Brazil and Venezuela. The uncontrolled surge of malaria in Venezuela, coupled with mass migration of Venezuelans to neighbouring countries and the upward trend in informal mining in the state, pose a serious threat to the broader region, especially to migrant, indigenous and mining populations, jeopardizing malaria elimination efforts. This study describes changes in the epidemiological profile of malaria in Roraima state related to time, place and populations at risk from 2016 to 2020. METHODS: De-identified malaria surveillance data were obtained from the Malaria Epidemiological Surveillance System from 2016 to 2020. Pearson's chi-square tested differences between imported and autochthonous cases. Multivariable logistic regression was used to identify risk factors for imported versus autochthonous cases by demographic characteristics. RESULTS: Odds of being an imported case were higher for Plasmodium falciparum cases (AOR = 2.08). However, as the number of cases from Venezuela decreased in 2020 following closure of the border, the proportion of P. falciparum cases increased markedly, from 6.24% in 2019 to 18.50% in 2020. Over the 5-year period, the odds of being an imported case among miners were about nine times higher than the general population (AOR = 8.99). The proportion of total malaria cases that were among indigenous people increased from 33.09% in 2016 to 54.83% in 2020. Indigenous children had a higher burden of malaria with over 40% of cases in children 0 to 9 years old, compared to 8% in non-indigenous children 0 to 9 years old. In some municipalities, place of infection differed from place of notification, with a large proportion of cases in these municipalities reporting in Boa Vista. CONCLUSIONS: Malaria remains a serious threat in Roraima state, especially among high-risk populations, such as miners, migrants, and indigenous people. As malaria cases have increased among indigenous people and miners, and the proportion of P. falciparum cases has increased, elimination efforts require understanding of these risk factors to tailor interventions appropriately. Furthermore, cross-border surveillance systems need to be urgently strengthened at formal and unofficial border points, especially since the border with Venezuela reopened in July 2021.

Larval habitats, species composition and distribution of malaria vectors in regions with autochthonous and imported malaria in Roraima state, Brazil.

BACKGROUND: Malaria control requires local action. Assessing the vector diversity and abundance provides information on the local malariogenic potential or risk of transmission. This study aimed to determine the Anopheles species composition, habitats, seasonal occurrence, and distribution in areas with autochthonous and imported malaria cases in Roraima State. METHODS: A longitudinal study was conducted from January 2017 to October 2018, sampling larvae and adult mosquitoes in three municipalities of Roraima State: Boa Vista, Pacaraima and São João da Baliza. These areas have different risks of malaria importation. Four to six mosquito larval habitats were selected for larval sampling at each municipality, along with two additional sites for adult mosquito collection. All larval habitats were surveyed every two months using a standardized larval sampling methodology and MosqTent for adult mosquitoes. RESULTS: A total of 544 Anopheles larvae and 1488 adult mosquitoes were collected from the three municipalities studied. Although the species abundance differed between municipalities, the larvae of Anopheles albitarsis s.l., Anopheles nuneztovari s.l. and Anopheles triannulatus s.l. were collected from all larval habitats studied while Anopheles darlingi were collected only from Boa Vista and São João da Baliza. Adults of 11 species of the genus Anopheles were collected, and the predominant species in Boa Vista was An. albitarsis (88.2%) followed by An. darlingi (6.9%), while in São João da Baliza, An. darlingi (85.6%) was the most predominant species followed by An. albitarsis s.l. (9.2%). In contrast, the most abundant species in Pacaraima was Anopheles braziliensis (62%), followed by Anopheles peryassui (18%). Overall, the majority of anophelines exhibited greater extradomicile than peridomicile-biting preference. Anopheles darlingi was the only species found indoors. Variability in biting times was observed among species and municipalities. CONCLUSION: This study revealed the composition of anopheline species and habitats in Boa Vista, Pacaraima and São João da Baliza. The species sampled differed in their behaviour with only An. darlingi being found indoors. Anopheles darlingi appeared to be the most important vector in São João da Baliza, an area of autochthonous malaria, and An. albitarsis s.l. and An. braziliensis in areas of low transmission, although there were increasing reports of imported malaria. Understanding the diversity of vector species and their ecology is essential for designing effective vector control strategies for these municipalities.

Severe long-delayed malaria caused by Plasmodium malariae in an elderly French patient.

BACKGROUND: Plasmodium malariae is the cause of the rare but severe form of malaria that sometimes affects individuals travelling to malaria-endemic regions. This report presents the unique case of a patient exhibiting severe malaria symptoms caused by P. malariae with no record of recent travel to any malaria-endemic areas. CASE PRESENTATION: An 81-year-old French woman was admitted to the emergency department with sustained fever and severe weakness for the past 5 days. She suffered from anaemia, thrombocytopenia, confusion, somnolence, pulmonary complications, and hypoxaemia. In the absence of any concrete aetiology that could explain the fever together with thrombocytopenia, physicians suspected malaria as a probable diagnosis. The LAMP-PCR and lateral flow test confirmed the presence of malaria parasite, Plasmodium sp. Microscopic examination (May-Grünwald Giemsa-stained thin blood smear) revealed the presence of trophozoites, schizonts, and gametocytes with 0.93 % parasitaemia. Conventional PCR amplification targeting 510 bp DNA fragment of small subunit ribosomal RNA (ssrRNA) and bidirectional sequencing identified the parasite as Plasmodium malariae. The travel history of this patient revealed her visits to several countries in Europe (Greece), North Africa (Tunisia and Morocco), and the West Indies (Dominican Republic). Of these, the latter was the only country known to be endemic for malaria at the time (three malaria parasite species were prevalent: Plasmodium falciparum, Plasmodium vivax, and P. malariae). The patient had most likely got infected when she visited the Dominican Republic in the summer of 2002. This time interval between the initial parasite infection (2002) till the onset of symptoms and its subsequent diagnosis (2020) is a reminder of the ability of P. malariae to persist in the human host for many years. CONCLUSIONS: This report highlights the persistent nature and ability of P. malariae to cause severe infection in the host even after a prolonged time interval.

Cross-border malaria in Northern Brazil.

BACKGROUND: Cross-border malaria is a major barrier to elimination efforts. Along the Venezuela-Brazil-Guyana border, intense human mobility fueled primarily by a humanitarian crisis and illegal gold mining activities has increased the occurrence of cross-border cases in Brazil. Roraima, a Brazilian state situated between Venezuela and Guyana, bears the greatest burden. This study analyses the current cross-border malaria epidemiology in Northern Brazil between the years 2007 and 2018. METHODS: De-identified data on reported malaria cases in Brazil were obtained from the Malaria Epidemiological Surveillance Information System for the years 2007 to 2018. Pearson's Chi-Square test of differences was utilized to assess differences between characteristics of cross-border cases originating from Venezuela and Guyana, and between border and transnational cases. A logistic regression model was used to predict imported status of cases. RESULTS: Cross-border cases from Venezuela and Guyana made up the majority of border and transnational cases since 2012, and Roraima remained the largest receiving state for cross-border cases over this period. There were significant differences in the profiles of border and transnational cases originating from Venezuela and Guyana, including type of movement and nationality of patients. Logistic regression results demonstrated Venezuelan and Guyanese nationals, Brazilian miners, males, and individuals of working age had heightened odds of being an imported case. Furthermore, Venezuelan citizens had heightened odds of seeking care in municipalities adjacent Venezuela, rather than transnational municipalities. CONCLUSIONS: Cross-border malaria contributes to the malaria burden at the Venezuela-Guyana-Brazil border. The identification of distinct profiles of case importation provides evidence on the need to strengthen surveillance at border areas, and to deploy tailored strategies that recognize different mobility routes, such as the movement of refuge-seeking individuals and of Brazilians working in mining.

First imported Plasmodium ovale malaria in Central America: case report of a Guatemalan soldier and a call to improve its accurate diagnosis.

The Mesoamerican Ministers of Health have set 2020 as the target for malaria elimination to be achieved in the region. Imported malaria cases are a potential threat to countries attempting elimination or working to prevent resurgence. We report the first imported Plasmodium ovale infection with molecular confirmation in Central America, which occurred in a Guatemalan soldier that had been deployed in Africa. The obstacles for its diagnosis using the standard microscopy technique and the need to improve its detection are discussed.

Aplicaciones de un modelo integral para el estudio de la malaria urbana en San Andrés de Tumaco, Colombia / Applications of a comprehensive model for the study of urban malaria in San Andrés de Tumaco, Colombia

Se analizaron las características epidemiológicas y factores asociados con la transmisión de la malaria urbana en el mundo, mediante la revisión de literatura publicada, en la cual se incluyeron libros, artículos científicos, revisiones de temas y reportes técnicos. La metodología aplicada se basó en la búsqueda de documentos y gestores en fuentes bibliográficas. Con los resultados se espera retratar la actualidad del fenómeno de malaria urbana en función de su carga de morbilidad y mortalidad, que sirve de base para el desarrollo de las investigaciones y estrategias pertinentes para su control.

A study was conducted of the epidemiological characteristics of urban malaria and the factors associated to its transmission worldwide by means of a review of published materials, including books, scientific papers, topic reviews and technical reports. The methodology applied was based on the search for documents and managers in bibliographic sources. Results are expected to provide a current picture of the morbidity and mortality burden of urban malaria, laying the foundations for relevant research into the topic and the development of control strategies.

Analysis of the direct and indirect costs of treatment of imported malaria in the Slovak Republic / Análise dos custos diretos e indiretos do tratamento da malária importada na República Eslovaca

This study analyzed the approximate cost of treatment of patients hospitalized with a diagnosis of imported malaria in Slovakia. Between 2003 and 2007, 15 patients with imported malaria were hospitalized. The mean direct cost of the treatment was 970.75 euros and the mean indirect cost was 53.15 euros. For the patient with the highest cost of treatment, the use of mefloquine prophylaxis would have represented only 0.5 percent of the total direct cost of treating the disease. Despite the partial resistance of plasmodia, malaria chemoprophylaxis is unequivocally a cheaper choice than subsequent treatment of malaria.

Análise do custo aproximado do tratamento dos doentes hospitalizados na Eslováquia com malária importada. Entre 2003 a 2007, foram internados 15 doentes com malária importada. Os custos médios diretos do tratamento foram avaliados em 920,75 euros e indireto em 53,15 euros. No doente com o custo mais elevado de tratamento, a utilização da profilaxia com mefloquina representaria somente 0,5 por cento do total dos custos diretos do tratamento da doença. Apesar da resistência parcial do plasmódio, a quimioprofilaxia da malária é inequivocamente uma opção mais econômica do que o tratamento posterior da malária.

Malária grave em Palmas, Estado do Tocantins: relato de caso / Severe malaria in Palmas, State of Tocantins: case report

Plasmodium falciparum causa a forma clínica mais grave da malária. Neste estudo, relatamos um caso de malária grave, através do acompanhamento do paciente e das anotações em prontuários médicos encontrados no Hospital Geral de Palmas. Discutimos o desfecho do caso e as complicações provocadas pela infecção, reconhecendo o risco potencial de ocorrência de malária grave em zona não endêmica, em consequência do retardo do tratamento e, a importância de intensificar medidas de vigilância que envolve todos os servidores das unidades de saúde, com ênfase para as áreas receptivas de migrantes oriundos de regiões endêmicas.

Plasmodium falciparum causes the most severe clinical form of malaria. In this study, we report a severe case of malaria, through following up the patient and from notes in the medical files at the Palmas General Hospital. We discuss the outcome of this case and the complications caused by this infection, recognizing the potential risk of occurrences of severe malaria in not-endemic areas because of the delay in treatment, and the importance of intensifying surveillance measures involving all health unit employees, with emphasis on the reception areas for migrants from endemic regions.

Malaria y embarazo: un caso importado de África / Malaria and pregnancy: an imported case from Africa

La malaria es un importante problema de saluden el mundo y es la principal causa de enfermedad ymuerte en muchas zonas tropicales y subtropicales, principalmente en África subsahariana donde las infecciones por Plasmodium falciparum son las másfrecuentes, situación particularmente importante, porque esta especie puede provocar malariagrave e incluso la muerte. Según la OrganizaciónMundial de la Salud se presentan entre 350 a 500millones de casos por año, la gran mayoría enÁfrica subsahariana, donde se registran el 60...

Malária grave importada: relato de caso / Severe imported malaria: case report

JUSTIFICATIVA E OBJETIVOS: A malária ainda representa um problema de saúde global. A forma grave da doença é causada principalmente por P. falciparum e pode cursar com complicações cerebrais, renais, pulmonares, hematológicas, circulatórias e hepáticas. O objetivo deste estudo foi relatar um caso de paciente portador de malária grave importada. RELATO DO CASO: Paciente do sexo masculino, 30 anos, pardo, filipino, marinheiro, proveniente de embarcação vinda da Nigéria, com história de dor abdominal no hipocôndrio direito, icterícia, febre e rebaixamento do nível de consciência. Os exames laboratoriais de admissão mostraram hiperbilirrubinemia de 50 mg/dL, acidose metabólica grave, trombocitopenia, creatinina de 5,6 mg/dL, leucocitose com desvio até metamielócitos. O escore APACHE II foi de 37, com risco de óbito de 88 por cento. Durante a internação foi diagnosticada malária por P. falciparum pelo teste de gota espessa. Mesmo com tratamento antimalárico adequado, o paciente evoluiu com insuficiência renal aguda necessitando de hemodiálise e síndrome de angústia respiratória aguda (SARA), necessitando de ventilação mecânica (VM), choque refratário tratado com aminas vasoativas, além de quadro hematológico, configurando um caso grave de disfunção de múltiplos de órgãos. Ainda apresentou pneumonia associada à VM e sepse relacionada ao uso de cateteres. Após a alta hospitalar, o paciente não apresentou seqüelas cerebral, pulmonar ou renal. CONCLUSÕES: Dos critérios definidores de malária grave descritos na literatura, o paciente preenchia: insuficiência renal aguda, síndrome da angústia respiratória aguda (SARA), acidose metabólica, alteração do nível de consciência, hemoglobinúria macroscópica, hiperparasitemia e hiperbilirrubinemia, que se relaciona a uma mortalidade maior que 10 por cento, na dependência do tratamento precoce e dos recursos disponíveis. A malária grave exige diagnóstico e tratamento intensivo rápidos, pois o atraso aumenta...

BACKGROUND AND OBJECTIVES: Malaria is still considered a major global health problem. The severity form of the disease is caused, mainly by P. falciparum and may occur together with cerebral, kidney, pulmonary, hematologic, circulatory and hepatic complications. This report is about a patient with a case of severe imported malaria. CASE REPORT: A 30-years-old man, mulatto, Philippine, sailor, coming from a ship arriving from Nigeria, with a history of abdominal pain on the right hypochondrium, jaundice, fever, decreased in the consciousness. Lab tests made upon his admission showed hyperbilirubinemia at a level of 50 mg/dL, severe metabolic acidosis, thrombocytopenia, creatinine levels of 5.6 mg/dL and leukocytosis with deviation through metamyelocytes. The APACHE II score was 37, with death estimated risk of 88 percent. During his stay at the hospital, P. Falciparum Malaria was diagnosed through the thick drop test. And, even with the adequate anti-malaria therapy, the patientÆs condition evolved to an acute renal failure requiring hemodialis; acute respiratory distress syndrome (ARDS); septic shock, and hematological disorders, forming a multiple organ dysfunction syndrome (MODS). After being discharged from the hospital, the patient did not present any cerebral, pulmonary or kidney sequel. CONCLUSIONS: From the criteria described in medical literature to define critical malaria, the patient fulfilled the following: acute renal failure, ARDS, metabolic acidosis, altered level of consciousness, macroscopic hemoglobinuria, hyperparasitism and hyperbilirubinemia, related to a lethality rate of over 10 percent, depending on early treatment and available resources. Severe malaria requires fast diagnosis allied to a quick access to an intensive care treatment, since any delay increases the morbid-mortality of the disease.