Sporotrichosis is an endemic mycosis caused by the species of the
Sporothrix
genus, and it is considered one of the most frequent subcutaneous mycoses in Mexico. This mycosis has become a relevant ...fungal infection in the last two decades. Today, much is known of its epidemiology and distribution, and its taxonomy has undergone revisions. New clinical species have been identified and classified through molecular tools, and they now include
Sporothrix schenckii sensu stricto
,
Sporothrix brasiliensis
,
Sporothrix globosa
, and
Sporothrix luriei
. In this article, we present a systematic review of sporotrichosis in Mexico that analyzes its epidemiology, geographic distribution, and diagnosis. The results show that the most common clinical presentation of sporotrichosis in Mexico is the lymphocutaneous form, with a higher incidence in the 0–15 age range, mainly in males, and for which trauma with plants is the most frequent source of infection. In Mexico, the laboratory diagnosis of sporotrichosis is mainly carried out using conventional methods, but in recent years, several researchers have used molecular methods to identify the
Sporothrix
species. The treatment of choice depends mainly on the clinical form of the disease, the host’s immunological status, and the species of
Sporothrix
involved. Despite the significance of this mycosis in Mexico, public information about sporotrichosis is scarce, and it is not considered reportable according to Mexico’s epidemiological national system, the “Sistema Nacional de Vigilancia Epidemiológica.” Due to the lack of data in Mexico regarding the epidemiology of this disease, we present a systematic review of sporotrichosis in Mexico, between 1914 and 2019, that analyzes its epidemiology, geographic distribution, and diagnosis.
Sporotrichosis is a chronic subcutaneous mycosis caused by the
species complex and it is considered an emerging opportunistic infection in countries with tropical and subtropical climates. The host's ...immune response has a main role in the development of this disease. However, it is unknown the features of the memory cellular immune response that could protect against the infection. Our results show that i.d. immunization in the ears of mice with inactivated
conidia (iC) combined with the cholera toxin (CT) induces a cellular immune response mediated by circulating memory CD4
T cells, which mainly produce interleukin 17 (IL-17). These cells mediate a strong delayed-type hypersensitivity (DTH) reaction. Systemic and local protection against
was mediated by circulating CD4
T cells. In contrast, the infection induces a potent immune response in the skin mediated by CD4
T cells, which have an effector phenotype that preferentially produce interferon gamma (IFN-γ) and mediate a transitory DTH reaction. Our findings prove the potential value of the CT as a potent skin adjuvant when combined with fungal antigens, and they also have important implications for our better understanding of the differences between the memory immune response induced by the skin immunization and those induced by the infection; this knowledge enhances our understanding of how a protective immune response against a
infection is developed.
Disseminated histoplasmosis is an AIDS-defining illness. Histoplasmosis is commonly misdiagnosed as tuberculosis. Nigeria has the second highest number of people living with HIV/AIDS in Africa. The ...present study was carried out to investigate the prevalence of skin sensitivity amongst Nigerians to histoplasmin.
A cross-sectional study was conducted in six centres across five geopolitical zones of Nigeria.
We recruited both healthy non-HIV and HIV-positive adults with CD4 count ≥ 350 cells/mm3 regardless of their ART status from March to May 2017. Skin tests were performed intradermally; induration ≥5 mm were considered to be histoplasmin positive.
750 participants were recruited from Lagos (n = 52), Yola (n = 156), Ilorin (n = 125), Calabar (n = 120), Ibadan (n = 202) and Benin (n = 95). 467 (62.3%) were HIV negative, 247 (32.9%) were HIV positive and 36 (4.8%) did not know their HIV status. A total of 32/735 (4.4%) participants had a positive skin test. Study centre (p<0.001), education (p = 0.002) and age (p = 0.005) appeared to be significantly associated with positive skin reactivity at the 0.5% significance level, while sex (p = 0.031) and occupation (p = 0.031) would have been significant at the 5% significance level. Males had a higher rate of reactivity than females (p = 0.031, 7% vs 3%). The highest positive rates were recorded from Benin City (13/86 (15%)) and Calabar (7/120 (6%)) and no positives were recorded in Lagos (p<0.001). HIV status was not statistically significant (p = 0.70).
Histoplasmosis diagnostics should be included in the Nigerian HIV guidelines. Epidemiological vigilance of progressive disseminated histoplasmosis should be considered by local health authorities.
In this study, molecular typing using Randomly Amplified Polymorphic DNA (RAPD-PCR) was conducted on 16 original isolates of
obtained from locusts (
ssp.
.) in Mexico (MX). The analysis included ...reference strains of the genus
sourced from various geographical regions. The isolates were identified by phenotypic (macro and micromorphology) and genotypic methods (RAPD-PCR and Amplified Fragment Length Polymorphisms (AFLP), through a multidimensional analysis of principal coordinates (PCoA) and a minimum spanning network (MST). Subsequently, Sequences-Characterized Amplified Region (SCAR) markers were developed for the molecular detection of
, these markers were chosen from polymorphic patterns obtained with 14 primers via RAPD-PCR. Phenotypic and genotypic characterization identified the MX isolates as
. Of all the polymorphic patterns obtained, only OPA04 and OPA05 were chosen, which presented species-specific bands for
, and further utilized to create SCAR markers through cloning and sequencing of the specific bands. The specificity of these two markers was confirmed via Southern hybridization. The SCAR markers (Ma-160
and Ma-151
) exhibit remarkable sensitivity, detecting down to less than 0.1 ng, as well as high specificity, as evidenced by their inability to cross-amplify or generate amplification with DNAs from other strains of
(as
) or different genera of entomopathogenic fungi (
and
). These SCAR markers yield readily detectable results, showcasing high reproducibility. They serve as a valuable tool, especially in field applications.
Sporotrichosis is the most common implantation mycosis caused by several species of the
complex. The gold standard for diagnosis is concerned with the isolation of the fungus; although, fresh ...examinations, staining, and biopsies are also helpful for this purpose. The sporotrichin is an antigenic complex comprised of a peptide-rhamnomannan, which is relevant with respect to pathogenic fungi; it is primarily used for serological and skin testing. We present a study regarding the use of sporotrichin as a diagnostic aid for cutaneous sporotrichosis. Furthermore, 138 cases with suspicion of sporotrichosis were included, 55 of which were proven through cultures. Moreover, out of these 55 cases, 52 (94.5%) tested positive for sporotrichin, while the negative cases corresponded to the disseminated cutaneous forms. We observed a sensitivity of 94.5% and a specificity of 95.2%. We consider that the use of sporotrichin as a skin test helps us as an auxiliary diagnosis before a positive sample culture.
Cell wall (CW) components of fungus Sporothrix schenckii are the major inductors antigens of immune responses. The immunodominant 60 kDa glycoprotein (gp60) has been shown to be associated with the ...virulence of this fungus but its role in experimental sporotrichosis is unknown. In this work, the immunological effects of CW-purified gp60 were investigated in a model of experimental subcutaneous sporotrichosis in normal and gp60-preimmunized C57BL/6 and BALB/c mice strains which were then infected with S. schenckii conidia. Results showed that both mice strains use different cytokine profiles in order to fight S. schenckii infection; C57BL/6 mice seem to use a Th17 response while BALB/c mice tend to depend on a Th1 profile. Preimmunization with gp60 showed a downregulatory effect on the immune response since cytokines levels were diminished in both strains. There were no significant differences in the magnitude of dorsoplantar inflammation between gp60-preimmunized and nonimmunized mice of both strains. However, skin lesions due to the infection in gp60-preimmunized mice were more severe in BALB/c than in C57BL/6 mice, suggesting that the antigen exerts a higher downregulatory effect on the Th1 response.
We utilized two-dimensional gel electrophoresis and immunoblotting
(2D-immunoblotting) with anti-Sporothrix schenckii antibodies to
identify antigenic proteins in cell wall preparations obtained from ...the
mycelial and yeast-like morphologies of the fungus. Results showed that
a 70-kDa glycoprotein (Gp70) was the major antigen detected in the cell
wall of both morphologies and that a 60-kDa glycoprotein was present
only in yeast-like cells. In addition to the Gp70, the wall from
filament cells showed four proteins with molecular weights of 48, 55,
66 and 67 kDa, some of which exhibited several isoforms. To our
knowledge, this is the first 2D-immunoblotting analysis of the S.
schenckii cell wall.
Metarhizium is a genus of entomopathogenic fungi that was initially classified into three species and varieties. More recently, DNA sequencing has improved the phylogenetic resolution of Metarhizium ...which now includes 30 species. The insect host ranges vary within the genus and some species such as M. robertsii have broad host ranges, while others such as M. acridum show a narrow host range and are restricted to the order Orthoptera. Metarhizium spp. are ubiquitous naturally occurring soil inhabiting fungi, and some are rhizosphere colonisers and their diversity has been attributed to various selective factors (habitat type, climatic conditions, specific associations with plants and insect hosts). Metarhizium have been used for the biological control of insect pests that affect economically important agricultural crops and have been tested under laboratory and field conditions for the control of insect vectors of human disease, showing the effectiveness of the fungus against the target pest. In Mexico, Metarhizium species have been used for the control of insect pests such as the spittlebug (Hemiptera: Cercopidae), and locusts (Orthoptera) that affect crops such as corn, bean and sugarcane. Biosafety studies, such as dermal and intragastric tests in mammalian models have also been carried out to ensure safety to humans and other animals. Metarhizium shows great promise as an alternative to chemical insecticides that has relatively low impact on human health and the environment. Key features of Metarhizium for biocontrol of insects are outlined with special reference to their utility in Mexico.
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