Non-fungal Disease Research Articles

Onychomycosis in patients with diabetes mellitus: Etiology, clinical features, and treatment response

Background: Onychomycosis accounts for 30% of all superficial mycoses and 50% of all nail diseases. One of the most studied predisposing factors is diabetes mellitus, with a frequency of onychomycosis of 31.5% in these patients. Many show resistance to standard therapeutics and have “polypharmacy”, which represents a risk for pharmacological interactions. Objective: The objective was to assess the clinical response to therapy, evaluate with histopathology, direct examination with KOH and white-calcofluor, and culture the most frequent etiologic agents associated with the development of onychomycosis in patients with diabetes mellitus. Materials and Methods: A non-randomized, uncontrolled, open-ended, prospective cohort study was conducted on 46 patients with onychomycosis and diabetes mellitus. Treatment was assigned according to clinical findings and specific indications for treatment. Results: From the samples taken for direct examination with KOH and calcofluor-white, culture, and histopathological study, positive results were: 39 (84.1%) patients to the direct examination, 32 (69.6%) to the culture, 27 (65.2%) with a positive histopathological study, and 17 (54.86%) to the calcofluor-white. On clinical evaluation, we found no treatment response in 8 patients (20%), a partial response in 14 patients (25%), and a complete response in 18 patients (45%). Out of the 46 patients evaluated initially, 25 persisted with onychomycosis after six months of follow-up. Conclusion: The prevalence of onychomycosis is increasing and requires correct diagnosis since there are other non-fungal diseases of the nails that resemble onychomycosis. Presumably, the immunosuppression of diabetes, its systemic affection, and the foot abnormalities of a diabetic patient cause more nail dystrophy, an increased fungal load, and treatment resistance.

Sustaining Sugarcane Production in Guatemala and Nicaragua Through Efficient Disease Management Approaches

Sugarcane occupies sizeable cropping area in Latin American countries especially in Guatemala and Nicaragua, where sugar industry substantially contributes to the national GDP as well as to foreign trade. In these countries, sugarcane cultivation faces challenges from different diseases caused by fungi, bacteria and virus. Among the diseases, dry stalk rot caused by five different fungal pathogens is the major disease constraint, impacting sugarcane production in the countries. The non-fungal diseases cause loss of vigour leading to varietal degeneration in sugarcane. Traditional disease management in sugarcane centres around host resistance to different diseases, and this approach remains as the most important in the Central American region. However, new variants (strains) with more virulence emerge in case of fungal pathogens and this phenomenon leads to varietal breakdown; thereby, resistant varieties become susceptible. Hence, other disease management options are employed, especially antagonistic and growth-promoting microbes of bacteria and fungi for the sustainable sugarcane production in the Guatemalan and Nicaraguan sugar mills. Additionally, degeneration in varieties caused by ratoon stunting is addressed through healthy seed nurseries. The review focuses on sugar scenario, major disease constraints, disease screening and resistance identification and other disease management options to sustain sugarcane sector in Guatemala and Nicaragua.

Straighthead and Agronomy Characters Testing for Selected Parent Lines and Hybrid Combinations at UAPB in 2011-2012

Straighthead disease is a physiological disorder in rice and the most widespread non-fungal disease of the U.S. straighthead greatly reduces rice yield. Straighthead studies were most conducted in the artificial field which was Arsenic amendment plots due to the similarity of straighthead symptoms of Arsenic damage. To evaluate the straighthead disease resistance in natural condition, 46 rice lines, including 24 inbred lines and 22 hybrid combinations which were developed from breading program, were chosen for straighthead and agronomy characters testing in a native soil where straighthead naturally induced in the past years at University of Arkansas at Pine Bluff (UAPB), Arkansas in 2011 and 2012. The straighthead of rice were rated from 0 to 9 levels, and 0 was the least straighthead disorder and 9 was the most severe straighthead disorder. Cocodrie (CCDR) was used as the check in this study. The results of 2011 showed that the yields of 8 entries were higher than the check CCDR. The straighthead scores of these 8 entries were 0 - 1 which indicated their resistance to straighthead. The rest of the entries had lower yields than check CCDR with straighthead scores 5 - 6 which indicated their moderate susceptibility to straighthead. The yields were negatively related to the straighthead scores (r = -0.9178, P

Varietal Degeneration in Sugarcane and its Management in India

Vegetative propagation in sugarcane favours accumulation of pathogens inside the canes and carryover of pathogenic inoculum through planting materials. Except foliar diseases, disease-infected setts serve as a primary source for disease spread for most of the diseases in the crop. In case of fungal diseases, planting infected setts leads to disease builds up in plant crop and probably death of the affected clump. However, in case of non-fungal diseases continuous accumulation of pathogens systemically leads to loss of vigour in sugarcane varieties referred to as ‘varietal degeneration’ and this results in loss of yield potential in elite commercial varieties. Past decades witnessed many such instances of degeneration in popular sugarcane varieties and their replacement with new varieties. With the development of precise molecular diagnostic tools, the associated pathogens were precisely identified. Under Indian conditions, it was found that combined or separate infections of viruses causing mosaic and yellow leaf (YL), phytoplasmas causing grassy shoot and leaf yellows and bacterium causing ratoon stunting disease are associated with varietal degeneration. The degeneration was rapid and severe when all these pathogens infect sugarcane together as compared to their separate infections. However, among all these diseases, YL contributes more towards degeneration of sugarcane varieties. The disease occurrence to epidemic levels in different states is a serious concern for sugar industry and due to that longevity of the affected varieties in the field is threatened. Meristem-tip culture combined with molecular diagnosis was found effective eliminate the pathogens efficiently from the cane. Developing disease-free nurseries is imperative to sustain productivity of sugarcane and to realize yield potential of popular sugarcane varieties in India.

Evaluation of Coccidioides Antigen Detection in Dogs with Coccidioidomycosis

Antigen detection has been reported to be a promising method for rapid diagnosis of coccidioidomycosis in humans. Coccidioides antigen detection has not been previously reported in dogs with coccidioidomycosis and was evaluated in 60 cases diagnosed based on detection of anti-Coccidioides antibodies at titers of 1:16 or more in serum. Controls included dogs with presumed histoplasmosis or blastomycosis, other fungal infections, or nonfungal diseases and healthy dogs. Urine and serum specimens were tested using an enzyme immunoassay for Coccidioides galactomannan antigen. Antibody testing was performed at commercial veterinary reference laboratories. Antigen was detected in urine or serum of 12 of 60 (20.0%), urine only in 2 of 57 (3.5%), and serum only in 11 of 58 (19.0%) dogs with coccidioidomycosis. Antigen was detected in the urine of 3 of 43 (7.0%) and serum of 1 of 37 (2.7%) dogs with histoplasmosis or blastomycosis but not in 13 dogs with other fungal infections (serum, 9; urine, 13), 41 dogs with nonfungal diseases (urine, 41; serum, 18), or healthy dogs (serum, 21; urine, 21). Detection of antigen was an insensitive method for diagnosis of coccidioidomycosis in dogs in which the diagnosis was based primarily upon detection of antibodies at titers of 1:16 or higher, and the highest sensitivity was in serum.

Development and Evaluation of a Latex Agglutination Test for the Serodiagnosis of Paracoccidioidomycosis

Paracoccidioidomycosis (PCM) is the most prevalent systemic mycosis in Latin America. It is caused by the dimorphic fungus Paracoccidioides brasiliensis. The immunodiffusion (ID) test is one of the most widely used techniques for PCM serologic diagnosis due to the simplicity and low costs of its execution. However, it requires trained and qualified people to execute it. The purpose of this study was to evaluate a latex particle agglutination (LA) test for the detection of anti-P. brasiliensis antibodies by using pooled crude exoantigens from the fungus. Fifty-one serum samples obtained from patients with PCM were tested. Positivity was observed in 84% (43/51) of these patients, and the agglutination patterns varied from small clumps with a cloudy background to large clumps with a clear background. The antibody titer reactivity ranged from 1:2 to 1:64. Cross-reactivity was observed in sera from patients with aspergillosis, histoplasmosis, and nonfungal disease. Serum samples obtained from healthy donors were not reactive. The sensitivity and specificity of the LA test were 84% and 81%, respectively. When comparing the LA test with the double-immunodiffusion test, we found an agreement of 92%. Further work is needed to improve the performance of the LA assay before it can be proposed as a reliable diagnostic tool, mainly in laboratories with little infrastructure.