Publications by authors named "Jon Eric Tongren"

Article Synopsis
  • Anopheles stephensi is a type of mosquito from Asia that is spreading in Africa, especially in cities of the Horn of Africa.
  • This mosquito is linked to malaria outbreaks, and researchers studied its role during a malaria outbreak in Ethiopia from April to July 2022.
  • They found that when An. stephensi was nearby, there were more malaria cases, and this study shows it could be a big problem for public health in urban areas.
View Article and Find Full Text PDF

Background: Vector bionomics are important aspects of vector-borne disease control programs. Mosquito-biting risks are affected by environmental, mosquito behavior and human factors, which are important for assessing exposure risk and intervention impacts. This study estimated malaria transmission risk based on vector-human interactions in northern Ghana, where indoor residual spraying (IRS) and insecticide-treated nets (ITNs) have been deployed.

View Article and Find Full Text PDF

The scale up of indoor residual spraying (IRS) and insecticide treated nets have contributed significantly to global reductions in malaria prevalence over the last two decades. However, widespread pyrethroid resistance has necessitated the use of new and more expensive insecticides for IRS. Partial IRS with pirimiphos-methyl in experimental huts and houses in a village-wide trial was evaluated against Anopheles gambiae s.

View Article and Find Full Text PDF

To date, the Republic of Rwanda has not systematically reported on distribution, diversity and malaria infectivity rate of mosquito species throughout the country. Therefore, we assessed the spatial and temporal variation of mosquitoes in the domestic environment, as well as the nocturnal biting behavior and infection patterns of the main malaria vectors in Rwanda. For this purpose, mosquitoes were collected monthly from 2010 to 2013 by human landing catches (HLC) and pyrethrum spray collections (PSC) in seven sentinel sites.

View Article and Find Full Text PDF
Article Synopsis
  • The decline in child mortality in Rwanda from 1996-2010 was significantly linked to increased malaria control measures, including indoor residual spraying (IRS) and insecticide-treated net (ITN) distribution.
  • Child mortality dropped by 61% during this period, and severe anemia in young children decreased by 71% from 2005 to 2010, attributed to rising use of malaria prevention strategies.
  • Enhanced access to effective malaria treatment and increased healthcare-seeking behaviors among caregivers contributed to these improvements, indicating that malaria interventions were crucial to the overall decline in child mortality in Rwanda.
View Article and Find Full Text PDF
Article Synopsis
  • In Rwanda, nationwide surveys in 2011 and 2013 monitored insecticide resistance in mosquitoes to assess threats to malaria control.
  • A total of 14,311 mosquitoes were tested, revealing significant resistance increases to certain insecticides like lambda-cyhalothrin, while bendiocarb and fenitrothion showed full susceptibility.
  • Genetic analysis of mosquitoes indicated various resistance alleles, with metabolic resistance also detected, marking this study as the first comprehensive look at insecticide resistance in Rwandan malaria vectors.
View Article and Find Full Text PDF

The largest recorded Ebola virus disease epidemic began in March 2014; as of July 2015, it continued in 3 principally affected countries: Guinea, Liberia, and Sierra Leone. Control efforts include contact tracing to expedite identification of the virus in suspect case-patients. We examined contact tracing activities during September 20-December 31, 2014, in 2 prefectures of Guinea using national and local data about case-patients and their contacts.

View Article and Find Full Text PDF

Background: During December 2006 to March 2007, a substantial increase in norovirus illnesses was noted in northern New England. We sought to identify institutional risk factors for norovirus outbreaks in northern New England long-term care facilities (LTCFs).

Methods: State health departments in Maine, New Hampshire, and Vermont distributed surveys to infection preventionists at all LTCFs in their respective states.

View Article and Find Full Text PDF

Objective: Our goal was to determine if the depiction of injury-prevention practices in children's movies is different from what was reported from 2 earlier studies, which showed infrequent depiction of characters practicing recommended safety behaviors.

Methods: The top-grossing 25 domestic G-rated (general audience) and PG-rated (parental guidance suggested) movies per year for 2003-2007 were included in this study. Movies or scenes were excluded if they were animated, not set in the present day, fantasy, documentary, or not in English.

View Article and Find Full Text PDF

Background: Plasmodium falciparum infection causes cerebral malaria (CM) in a subset of patients with anti-malarial treatment protecting only about 70% to 80% of patients. Why a subset of malaria patients develops CM complications, including neurological sequelae or death, is still not well understood. It is believed that host immune factors may modulate CM outcomes and there is substantial evidence that cellular immune factors, such as cytokines, play an important role in this process.

View Article and Find Full Text PDF

Background: Plasmodium falciparum can cause a diffuse encephalopathy known as cerebral malaria (CM), a major contributor to malaria associated mortality. Despite treatment, mortality due to CM can be as high as 30% while 10% of survivors of the disease may experience short- and long-term neurological complications. The pathogenesis of CM and other forms of severe malaria is multi-factorial and appear to involve cytokine and chemokine homeostasis, inflammation and vascular injury/repair.

View Article and Find Full Text PDF

Antibodies that bind to Fc receptors and activate complement are implicated in the efficient control of pathogens, but the processes that regulate their induction are still not well understood. To investigate antigen-dependent factors that regulate class switching, we have developed an in vivo model of class switching to immunoglobulin G2b (IgG2b) using the malaria antigen Plasmodium falciparum merozoite surface protein 2 (MSP2). C57BL/6 mice were immunized with recombinant proteins representing discrete domains of MSP2, and a T-cell epitope (C8) was identified within the conserved C terminus of the protein that preferentially induces IgG2b antibodies.

View Article and Find Full Text PDF

A vaccine trial was conducted to determine the efficacy of a multicomponent candidate vaccine, FALVAC-1, against Plasmodium falciparum in Aotus nancymai monkeys. After two immunizations, animals were challenged intravenously with parasites of the Vietnam Oak Knoll (FVO) strain of P. falciparum.

View Article and Find Full Text PDF

Understanding the regulation of immune responses is central for control of autoimmune and infectious disease. In murine models of autoimmunity and chronic inflammatory disease, potent regulatory T lymphocytes have recently been characterized. Despite an explosion of interest in these cells, their relevance to human disease has been uncertain.

View Article and Find Full Text PDF

The Roll Back Malaria campaign vowed to halve the global burden of malaria in ten years but, midway into that campaign, few new malaria control tools have been introduced, and many established methods appear to be failing with effective chemotherapy being perhaps the most problematic. It has been repeatedly argued that the discovery and implementation of a safe and effective vaccine against malaria is a major priority in the control of the disease. Indeed, many malaria control experts believe that sustainable reductions in malaria control will be nigh on impossible in the absence of such a vaccine.

View Article and Find Full Text PDF

FALVAC-1, a vaccine against Plasmodium falciparum was developed by joining 21 epitopes from P. falciparum vaccine antigens and an universal T helper epitope from tetanus toxoid. Since adjuvants influence different aspects of immune responses, in this study we investigated the effect of four adjuvants aluminum hydroxide (alum), nonionic copolymer adjuvant P1005 (water-in-oil emulsion), CpG oligodeoxynucleotides (ODN), and QS-21 in eliciting immune responses in outbred mice.

View Article and Find Full Text PDF