scholarly journals Impact of Mosquito Bites on Asexual Parasite Density and Gametocyte Prevalence in Asymptomatic Chronic Plasmodium falciparum Infections and Correlation with IgE and IgG Titers

2012 ◽  
Vol 80 (6) ◽  
pp. 2240-2246 ◽  
Author(s):  
Ramatoulaye Lawaly ◽  
Lassana Konate ◽  
Laurence Marrama ◽  
Ibrahima Dia ◽  
Diawo Diallo ◽  
...  
Keyword(s):  
Immune Response ◽  
Plasmodium Falciparum ◽  
Salivary Gland ◽  
Parasite Density ◽  
Parasite Prevalence ◽  
Asexual Parasite ◽  
Salivary Gland Extract ◽  
Th2 Response ◽  
Content Type ◽  
Asymptomatic Infections

ABSTRACTAn immunomodulatory role of arthropod saliva has been well documented, but evidence for an effect onPlasmodiumsp. infectiousness remains controversial. Mosquito saliva may orient the immune response toward a Th2 profile, thereby priming a Th2 response against subsequent antigens, includingPlasmodium. Orientation toward a Th1 versus a Th2 profile promotes IgG and IgE proliferation, respectively, where the former is crucial for the development of an efficient antiparasite immune response. Here we assessed the direct effect of mosquito bites on the density ofPlasmodium falciparumasexual parasites and the prevalence of gametocytes in chronic, asymptomatic infections in a longitudinal cohort study of seasonal transmission. We additionally correlated these parasitological measures with IgE and IgG antiparasite and anti-salivary gland extract titers. The mosquito biting density was positively correlated with the asexual parasite density but not asexual parasite prevalence and was negatively correlated with gametocyte prevalence. Individual anti-salivary gland IgE titers were also negatively correlated with gametocyte carriage and were strongly positively correlated with antiparasite IgE titers, consistent with the hypothesis that mosquito bites predispose individuals to develop an IgE antiparasite response. We provide evidence that mosquito bites have an impact on asymptomatic infections and differentially so for the production of asexual and sexual parasites. An increased research focus on the immunological impact of mosquito bites during asymptomatic infections is warranted, to establish whether strategies targeting the immune response to saliva can reduce the duration of infection and the onward transmission of the parasite.

scholarly journals Inside Scoop on Outside Proteins

2013 ◽  
Vol 82 (3) ◽  
pp. 921-923
Author(s):  
Jeffrey D. Dvorin
Keyword(s):  
Immune Response ◽  
Plasmodium Falciparum ◽  
Life Cycle ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Current Issue ◽  
Detailed Examination ◽  
Content Type ◽  
Human Malaria ◽  
Essential Step

ABSTRACTInvasion into red blood cells is an essential step in the life cycle of parasites that cause human malaria. Antibodies targeting the key parasite proteins in this process are important for developing a protective immune response. In the current issue, Boyle and colleagues provide a detailed examination ofPlasmodium falciparuminvasion and specifically illuminate the fate of surface-exposed parasite proteins during and immediately after invasion.

scholarly journals In vitro analysis of human immune response (IgG) against salivary gland extract of dengue vector from dengue hemorrhagic fever (DHF) endemic area in Jember, Indonesia

2021 ◽  
Vol 913 (1) ◽  
pp. 012090
Author(s):  
R Oktarianti ◽  
D R Damara ◽  
S U R Qudsiyah ◽  
S Wathon ◽  
K Senjarini
Keyword(s):  
Immune Response ◽  
Salivary Gland ◽  
Endemic Area ◽  
Mosquito Species ◽  
Host Immune System ◽  
Salivary Gland Extract ◽  
Gland Extract ◽  
Human Immune Response ◽  
Human Immune

Abstract The mosquito species Ae. aegyptiand Ae. albopictusare two potential vectors of dengue fever. The salivary glands of these species contain substances that play a role in the transmission of pathogens. These include vasodilators and immunomodulatory compounds. Immunomodulatory components can modulate the host immune system by producing specific antibodies (IgG). This study aims to investigate the human immune response (IgG) against the salivary gland extract of Ae. aegyptiand Ae. albopictus. Samples were collected from individuals who were Dengue patients, as well as healthy individuals and neonates from the Jember endemic area. Results show that the levels of IgG response vary across the individual. Generally, Dengue patients and healthy people in the DHF-endemic area had higher levels of IgG. The highest immune response was found in DHF patients, followed by healthy persons, and finally the neonate samples, respectively.

scholarly journals Impact of an Irrigation Dam on the Transmission and Diversity of Plasmodium falciparum in a Seasonal Malaria Transmission Area of Northern Ghana

2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Eric Kyei-Baafour ◽  
Bernard Tornyigah ◽  
Benjamin Buade ◽  
Langbong Bimi ◽  
Abraham R. Oduro ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Malaria Transmission ◽  
Parasite Density ◽  
Parasite Prevalence ◽  
Dry Season ◽  
Water Bodies ◽  
Northern Ghana ◽  
Wet Season ◽  
Transmission Area ◽  
Dam Site

Water bodies such as dams are known to alter the local transmission patterns of a number of infectious diseases, especially those transmitted by insects and other arthropod vectors. The impact of an irrigation dam on submicroscopic asexual parasite carriage in individuals living in a seasonal malaria transmission area of northern Ghana was investigated. A total of 288 archived DNA samples from two cross-sectional surveys in two communities in the Bongo District of Northern Ghana were analysed. Parasite density was determined by light microscopy and PCR, and parasite diversity was assessed by genotyping of the polymorphic Plasmodium falciparum msp2 block-3 region. Submicroscopic parasitaemia was estimated as the proportional difference between positive samples identified by PCR and microscopy. Dry season submicroscopic parasite prevalence was significantly higher (71.0%, p=0.013) at the dam site compared with the nondam site (49.2%). Similarly, wet season submicroscopic parasite prevalence was significantly higher at the dam site (54.5%, p=0.008) compared with the nondam site (33.0%). There was no difference in parasite density between sites in the dry season (p=0.90) and in the wet season (p=0.85). Multiplicity of infection (MOI) based on PCR data was significantly higher at the dam site compared with the nondam site during the dry season (p<0.0001) but similar between sites during the wet season. MOI at the nondam site was significantly higher in the wet season than in the dry season (2.49, 1.26, p<0.0001) but similar between seasons at the dam site. Multivariate analysis showed higher odds of carrying submicroscopic parasites at the dam site in both dry season (OR = 7.46, 95% CI = 3.07–18.15) and in wet season (OR = 1.73, 95% CI = 1.04–2.86). The study findings suggest that large water bodies impact year-round carriage of submicroscopic parasites and sustain Plasmodium transmission.

scholarly journals The IL-33/ST2 Axis Is Associated with Human Visceral Leishmaniasis and Suppresses Th1 Responses in the Livers of BALB/c Mice Infected with Leishmania donovani

mBio ◽  
2013 ◽  
Vol 4 (5) ◽  
Author(s):  
Octavie Rostan ◽  
Jean-Pierre Gangneux ◽  
Claire Piquet-Pellorce ◽  
Christelle Manuel ◽  
Andrew N. J. McKenzie ◽  
...  
Keyword(s):  
Immune Response ◽  
Visceral Leishmaniasis ◽  
Leishmania Donovani ◽  
Parasite Burden ◽  
World Health ◽  
Enzyme Linked Immunosorbent Assay ◽  
Cytokine Signaling ◽  
Th2 Response ◽  
Content Type ◽  
Th1 Cytokines

ABSTRACT During visceral leishmaniasis, the control of hepatic parasite burden is mainly due to granuloma assembly in a microenvironment consisting of both Th1 and Th2 components. Using enzyme-linked immunosorbent assay (ELISA) dosages, quantitative PCR (qPCR), immunohistochemistry, and flow cytometry, we studied the role of interleukin-33 (IL-33), a recently described cytokine signaling through the ST2 receptor, during visceral leishmaniasis. We showed that a higher level of IL-33 was detected in the serum of patients with visceral leishmaniasis than in that from healthy donors and demonstrated the presence of IL-33+ cells in a liver biopsy specimen from a patient. Similarly, in BALB/c mice experimentally infected with L. donovani, a higher level of IL-33 was detected in the serum, as well as the presence of IL-33+ cells and ST2+ cells in the mouse liver. In ST2−/− BALB/c mice, better control of the hepatic parasite burden and reduced hepatomegaly were observed. This was associated with strong induction of Th1 cytokines (gamma interferon [IFN-γ] and IL-12) compared to the level in wild-type (WT) mice and better recruitment of myeloid cells associated with strongly induced chemokines (CCL2 and CXCL2) and receptors (CCR2 and CXCR2). Conversely, BALB/c mice treated twice weekly with recombinant IL-33 showed a dramatically reduced induction of Th1 cytokines and delayed inhibition of monocyte and neutrophil recruitment in the liver, which was associated with reduced KC/CXCL1 and CXCR2 expression. Taken together, our results suggest that IL-33 could be a new deleterious regulator of the hepatic immune response against Leishmania donovani, via the repression of the Th1 response and myeloid cell recruitment. IMPORTANCE Visceral leishmaniasis is a life-threatening systemic disease due to the Leishmania protozoa L. infantum and L. donovani and is ranked by the World Health Organization as the second most important protozoan parasitic disease after malaria for its grave morbidity, high mortality, and global distribution. Leishmania parasites subvert the host’s immune response to propagate to target organs, including the spleen, the bone marrow, and the liver. Control of hepatic parasite burdens depends on a delicate and poorly understood Th1/Th2 immune balance. To better understand this complex immune response, new cytokines are interesting targets for research studies. IL-33 is a newly described cytokine usually associated with Th2 response and involved in different diseases, including infectious diseases and hepatitis. Our results suggest that IL-33 could be a new factor of susceptibility and a potential prognostic marker during visceral leishmaniasis.

scholarly journals Selenium Status Alters the Immune Response and Expulsion of Adult Heligmosomoides bakeri Worms in Mice

2013 ◽  
Vol 81 (7) ◽  
pp. 2546-2553 ◽  
Author(s):  
Allen D. Smith ◽  
Lumei Cheung ◽  
Ethiopia Beshah ◽  
Terez Shea-Donohue ◽  
Joseph F. Urban
Keyword(s):  
Immune Response ◽  
Small Intestine ◽  
Metabolic Activity ◽  
Surrounding Tissue ◽  
Th2 Response ◽  
Content Type ◽  
Adequate Diet ◽  
Th2 Immune Response ◽  
Heligmosomoides Bakeri ◽  
Deficient Mice

ABSTRACTHeligmosomoides bakeriis a nematode with parasitic development exclusively in the small intestine of infected mice that induces a potent STAT6-dependent Th2 immune response. We previously demonstrated that host protective expulsion of adultH. bakeriworms from a challenge infection was delayed in selenium (Se)-deficient mice. In order to explore mechanisms associated with the delayed expulsion, 3-week-old female BALB/c mice were placed on a torula yeast-based diet with or without 0.2 ppm Se, and after 5 weeks, they were inoculated withH. bakeriinfective third-stage larvae (L3s). Two weeks after inoculation, the mice were treated with an anthelmintic and then rested, reinoculated with L3s, and evaluated at various times after reinoculation. Analysis of gene expression in parasite-induced cysts and surrounding tissue isolated from the intestine of infected mice showed that the local-tissue Th2 response was decreased in Se-deficient mice compared to that in Se-adequate mice. In addition, adult worms recovered from Se-deficient mice had higher ATP levels than worms from Se-adequate mice, indicating greater metabolic activity in the face of a suboptimal Se-dependent local immune response. Notably, the process of worm expulsion was restored within 2 to 4 days after feeding a Se-adequate diet to Se-deficient mice. Expulsion was associated with an increased local expression of Th2-associated genes in the small intestine, intestinal glutathione peroxidase activity, secreted Relm-β protein, anti-H. bakeriIgG1 production, and reduced worm fecundity and ATP-dependent metabolic activity.

scholarly journals Increased investment in gametocytes in asymptomatic Plasmodium falciparum infections in the wet season

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Colins O. Oduma ◽  
Sidney Ogolla ◽  
Harrysone Atieli ◽  
Bartholomew N. Ondigo ◽  
Ming-Chieh Lee ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Limit Of Detection ◽  
Parasite Prevalence ◽  
Dry Season ◽  
Control Measures ◽  
Wet Season ◽  
Western Kenya ◽  
Vector Abundance ◽  
Asymptomatic Infections ◽  
Asymptomatic Individuals

Abstract Background Transmission stemming from asymptomatic infections is increasingly being recognized as a threat to malaria elimination. In many regions, malaria transmission is seasonal. It is not well understood whether Plasmodium falciparum modulates its investment in transmission to coincide with seasonal vector abundance. Methods We sampled 1116 asymptomatic individuals in the wet season, when vectors are abundant, and 1743 in the dry season, in two sites in western Kenya, representing different transmission intensities (Chulaimbo, moderate transmission, and Homa Bay, low transmission). Blood samples were screened for P. falciparum by qPCR, and gametocytes by pfs25 RT-qPCR. Results Parasite prevalence by qPCR was 27.1% (Chulaimbo, dry), 48.2% (Chulaimbo, wet), 9.4% (Homabay, dry), and 7.8% (Homabay, wet). Mean parasite densities did not differ between seasons (P = 0.562). pfs25 transcripts were detected in 119/456 (26.1%) of infections. In the wet season, fewer infections harbored detectable gametocytes (22.3% vs. 33.8%, P = 0.009), but densities were 3-fold higher (wet: 3.46 transcripts/uL, dry: 1.05 transcripts/uL, P < 0.001). In the dry season, 4.0% of infections carried gametocytes at moderate-to-high densities likely infective (> 1 gametocyte per 2 uL blood), compared to 7.9% in the wet season. Children aged 5–15 years harbored 76.7% of infections with gametocytes at moderate-to-high densities. Conclusions Parasites increase their investment in transmission in the wet season, reflected by higher gametocyte densities. Despite increased gametocyte densities, parasite density remained similar across seasons and were often below the limit of detection of microscopy or rapid diagnostic test, thus a large proportion of infective infections would escape population screening in the wet season. Seasonal changes of gametocytemia in asymptomatic infections need to be considered when designing malaria control measures.

scholarly journals Potent Plasmodium falciparum Gametocytocidal Activity of Diaminonaphthoquinones, Lead Antimalarial Chemotypes Identified in an Antimalarial Compound Screen

2014 ◽  
Vol 59 (3) ◽  
pp. 1389-1397 ◽  
Author(s):  
Takeshi Q Tanaka ◽  
W. Armand Guiguemde ◽  
David S. Barnett ◽  
Maxim I. Maron ◽  
Jaeki Min ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Late Stage ◽  
Parasite Clearance ◽  
Asexual Parasite ◽  
Content Type ◽  
Drug Candidates ◽  
Control Programs ◽  
Parasite Stage ◽  
Asymptomatic Individuals ◽  
Gametocytocidal Activity

ABSTRACTForty percent of the world's population is threatened by malaria, which is caused byPlasmodiumparasites and results in an estimated 200 million clinical cases and 650,000 deaths each year. Drug resistance has been reported for all commonly used antimalarials and has prompted screens to identify new drug candidates. However, many of these new candidates have not been evaluated against the parasite stage responsible for transmission, gametocytes. IfPlasmodium falciparumgametocytes are not eliminated, patients continue to spread malaria for weeks after asexual parasite clearance. Asymptomatic individuals can also harbor gametocyte burdens sufficient for transmission, and a safe, effective gametocytocidal agent could also be used in community-wide malaria control programs. Here, we identify 15 small molecules with nanomolar activity against late-stage gametocytes. Fourteen are diaminonaphthoquinones (DANQs), and one is a 2-imino-benzo[d]imidazole (IBI). One of the DANQs identified, SJ000030570, is a lead antimalarial candidate. In contrast, 94% of the 650 compounds tested are inactive against late-stage gametocytes. Consistent with the ineffectiveness of most approved antimalarials against gametocytes, of the 19 novel compounds with activity against known anti-asexual-stage targets, only 3 had any strong effect on gametocyte viability. These data demonstrate the distinct biology of the transmission stages and emphasize the importance of screening for gametocytocidal activity. The potent gametocytocidal activity of DANQ and IBI coupled with their efficacy against asexual parasites provides leads for the development of antimalarials with the potential to prevent both the symptoms and the spread of malaria.

scholarly journals Plasmodium falciparum and Helminth Coinfections Increase IgE and Parasite-Specific IgG Responses

2021 ◽  
Author(s):  
Rebeca Santano ◽  
Rocío Rubio ◽  
Berta Grau-Pujol ◽  
Valdemiro Escola ◽  
Osvaldo Muchisse ◽  
...  
Keyword(s):  
Immune Response ◽  
Plasmodium Falciparum ◽  
Previous Exposure ◽  
Content Type ◽  
Current Infection ◽  
Specific Igg ◽  
Antibody Profile

Coinfection with Plasmodium falciparum and helminths may impact the immune response to these parasites because they induce different immune profiles. We compared the antibody profile between groups of Mozambican individuals defined by P. falciparum and helminth previous exposure and/or current infection.

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