Tropical Medicine

SARS and its treatment strategies Chun-Song Hu, Tengiz Tkebuchava Asian Pacific Journal of Tropical Medicine 2019 12(3):95-97 This paper briefly review severe acute respiratory syndrome, a devastating disease which broke out 15 years ago, and its treatment strategies. With the newly discovered SARSr-CoV strain in Yunnan, China, and the help of new technologies such as RNA interference, DNA vaccines, CRISPR technology and base editing, and intervention of RT-ABCDEF (iRT-ABCDEF), a standardized comprehensive program, people can better fight severe acute respiratory syndrome and other major virus-communicable diseases like highly pathogenic avian influenza and dengue fever with these powerful tools in the future.

Phyllanthus acidus (L.) Skeels and Rhinacanthus nasutus (L.) Kurz leaf extracts suppress melanogenesis in normal human epidermal melanocytes and reconstitutive skin culture Moragot Chatatikun, Takeshi Yamauchi, Kenshi Yamasaki, Anchalee Chiabchalard, Setsuya Aiba Asian Pacific Journal of Tropical Medicine 2019 12(3):98-105 Objective: To determine the effect of extracts from Phyllanthus acidus (P. acidus) (L.) Skeels and Rhinacanthus nasutus (R. nasutus) (L.) Kurz leaves on melanogenesis and the underlying mechanism in normal human epidermal melanocytes (NHEM) and a reconstitutive skin model. Methods: NHEM and a reconstitutive skin model were stimulated with ethanol extracts of P. acidus (L.) Skeels and R. nasutus (L.) Kurz leaves. mRNA expression of microphthalmia-associated transcription factor (MITF), tyrosinase (TYR), tyrosinase-related protein 1 (TYRP1) and dopachrome tautomerase (DCT) were examined by real-time PCR. The melanin content in NHEM was also measured. Moreover, protein levels of tyrosinase were determined using western blot analysis. Results: In NHEM and the reconstitutive skin model, ethanol extracts from P. acidus (at 12.5 and 25.0 μg/mL) and R. nasutus (at 6.25 and 12.50 μg/mL) significantly diminished mRNA expression of MITF, TYR, TYRP1 and DCT in a concentration-dependent manner. P. acidus and R. nasutus extracts also reduced the amount of melanin in α-MSH-stimulated NHEM. Moreover, P. acidus and R. nasutus extracts markedly suppressed tyrosinase at the translational level in the reconstitutive skin model. Conclusions: P. acidus and R. nasutus extracts significantly reduced melanogenesis in NHEM and the reconstitutive skin model, suggesting that P. acidus and R. nasutus extracts can inhibit melanin synthesis through downregulation of MITF, TYR, TYRP1 and DCT. Therefore, the ethanol extracts of P. acidus and R. nasutus contain compounds that have the potential for development as a skin lightening agent for the treatment of hyperpigmentation disorder or melasma.

Antihydatic and immunomodulatory effects of Algerian propolis ethanolic extract: In vitro and in vivo study Nahla Deghbar, Dalila Mezioug, Touri Kahina, Yacine-Miloud Medjdoub, Chafia Touil- Boukoffa Asian Pacific Journal of Tropical Medicine 2019 12(3):106-116 Objective: To evaluate the in vitro and in vivo effect of the Algerian propolis ethanolic extract (EEP) against Echinococcus granulosus (E. granulosus) infection. Methods: In vitro scolicidal activity of EEP was investigated on the protoscolices of hydatid cyst. This in vitro study was conducted by using an in vivo assay. BALB/c mice were inoculated with E. granulosus and treated with propolis for three months. Hydatid cysts development was assessed. Nitric oxide (NO), tumor necrosis factor alpha (TNF-α) production and inducible NO synthase, NF-κB, and TNF-α spleen expression were estimated by Griess method and immunofluorescence respectively. Results: Our study revealed that EEP has a high scolicidal activity against E. granulosus. Oral administration of EEP decreased TNF-α, NF-κB and inducible NO synthase expression in the spleen tissues in the CE+EEP group, in comparison with the CE group. Concomitantly, EEP treatment caused an important systemic decrease in NO and TNF-α levels. These findings are associated with the reduction of CE development. Conclusions: This is the first report demonstrating with interest the antihydatic and immunomodulatory effects of the Algerian EEP, suggesting its therapeutic potential for the hydatid disease treatment.

Chemical composition of Mentha suaveolens and Pinus halepensis essential oils and their antibacterial and antioxidant activities Abdelhakim Bouyahya, Omar Belmehdi, Jamal Abrini, Nadia Dakka, Youssef Bakri Asian Pacific Journal of Tropical Medicine 2019 12(3):117-122 Objective: To determin the chemical compounds of Mentha suaveolens (M. suaveolens) and Pinus halepensis (P. halepensis) essential oils (Eos) and evaluate their antioxidant and antibacterial activities. Methods: The chemical composition of P. halepensis and M. suaveolens EOs was determined by GC-MS analysis. The antioxidant activity was evaluated using DPPH, ABTS and FRAP assays. The antibacterial effect was tested against 6 bacterial strains using the well diffusion method and micro-dilution assay. Results: The major components of P. halepensis EOs were β-caryophyllene (28.04%), myrcene (23.81%) and α-pinene (12.02%). However, piperitenone oxid (56.28%), piperitenone (11.64%) and pulegone (6.16%) were the major components of M. suaveolens EOs. M. suaveolens EOs showed remarkable antioxidant activities compared with P. halepensis EOs, showing antioxidant capacity values of IC50=(64.76±2.24) μg/mL, IC50=(82.73±3.34) μg/mL, and IC50=(93.35±4.45) μg/mL, revealed by DPPH, ABTS and FRAP assays, respectively. However, P. halepensis EOs showed interesting antibacterial effects against all bacterial strains. The most sensible strains to P. halepensis EOs were Staphylococcus aureus [(34.00±0.50) mm], Listeria monocytogenes [(31.00±1.50)] mm and Proteus mirabilis [(29.00±2.25)mm]. Furthermore, the lowest minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values were revealed by P. halepensis EOs against Staphylococcus aureus [MIC=MBC=0.125% (v/v)] and Listeria monocytogenes [MIC=MBC=0.25% (v/v)]. Conclusions: P. halepensis and M. suaveolens EOs contain bioactive compounds that could have potential applications against bacterial infections and oxidative stress related diseases as well as for food conservation. However, further investigations are necessary to isolate and investigate the action mechanisms of these bioactive compounds.

Isolation and structural elucidation of antifungal compounds from Curcuma amada Jesmin Akter, Kensaku Takara, Md. Zahorul Islam, Md. Amzad Hossain, Ayako Sano, De-Xing Hou Asian Pacific Journal of Tropical Medicine 2019 12(3):123-129 Objective: To isolate and identify the antifungal compounds from Curcuma amada. Methods: The antifungal activity was measured by the diameter of colonies grown on Petri dish, microscopic observation, and CLSI microdilution methods. The antifungal compounds were isolated through bioactivity guided purification by using silica gel and high-performance liquid chromatography. Structural identification of the antifungal compounds was conducted using 1H NMR, 13C NMR, and liquid chromatography-tandem mass spectrometry. Results: The purified antifungal compounds were zederone and furanodienone. These two compounds showed dose-dependent antifungal activity against Fusarium solani sensu lato. The concentration required for 50% growth inhibition (IC50) of FSSL ranged from 115 to 129 μM and 82 to 91 μM for zederone and furanodienone, respectively. Conclusion: This study suggested that the isolated compounds from Curcuma amada could be promising natural antifungal agents to control the diseases caused by Fusarium solani sensu lato.

Status of intestinal parasitic infections among rural and urban populations, southwestern Iran Molouk Beiromvand, Esmat Panabad, Abdollah Rafiei Asian Pacific Journal of Tropical Medicine 2019 12(3):130-136 Objective: To evaluate the prevalence and risk factors of intestinal parasitic infections in the urban and rural areas of Shushtar County, southwest Iran. Methods: A total of 1 008 fecal samples were analyzed by direct smear examination, formalin-ether concentration, and Ziehl-Neelsen and trichrome staining; furthermore, PCR was used to distinguish Trichostrongylus and hookworm species based on 28S rRNA gene. Results: Totally, 16.0% cases tested positive, either with a pathogenic or a non-pathogenic parasite. Protozoa were detected in 14.0%, helminths in 1.0%, protozoa and helminth co-infections were detected in 0.3%, and co-infections of two protozoa were detected in 0.7% of cases. The most common protozoa and helminths were Giardia duodenalis (7.7%) and Trichostrongylus spp. (0.5%), respectively. Among five microscopy Trichostrongylus positive cases, Trichostrongylus culbriformis was successfully identified in three isolates by sequencing. In the rural areas, the prevalence of parasitic infection was higher (9.8%) than that in the urban areas (6.2%). A significant association was found between educational level, type of drinking water, animals contact, hand-washing, and clinical symptoms. Conclusions: This study indicates that intestinal parasitic infections remain as a public health priority in Shushtar County. It seems that drinking water and environmental sanitation are the main risk factors of parasitic infections in rural areas.

X-linked Toll-like receptor 7 polymorphism associated with susceptibility to Chikungunya Fever Daniela M Rauseo, Mercedes Fernández-Mestre Asian Pacific Journal of Tropical Medicine 2019 12(3):137-141 Objective: To investigate the association between TLR3 and TLR7 polymorphisms with susceptibility and clinical manifestations of Chikungunya Fever. Methods: A total of 177 individuals were studied: 73 patients with a confirmed diagnosis for Chikungunya virus and 104 non-infected individuals. Polymorphisms were determined by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP). Results: Our analysis showed an increased CC genotype frequency of the TLR7 rs3853839 polymorphism in male patients compared to control (29% versus 2%, respectively; OR=20.69; 95 % CI= 2.55-167.36; P<0.001). Furthermore, arthritis (acute and chronic) was frequently found in CC male patients. On the contrary, 65% of CG carriers were no-infected males (29% versus 65%, respectively; OR=0.23, 95% CI=0.48-3.04; P=0.002). Finally, we observed a higher frequency of lymphopenia in CG male patients (CG=666.86±233.77, GG=1,314.27±752.29 cells/mm3, P=0.047). Conclusions: Our results suggest the TLR7 rs3853839 polymorphism is associated with lymphopenia and increased susceptibility to Chikungunya Fever in males.

Occurrence of Escherichia coli virulence genes in feces of wild birds from Central Italy Fabrizio Bertelloni, Errica Lunardo, Guido Rocchigiani, Renato Ceccherelli, Valentina Viginia Ebani Asian Pacific Journal of Tropical Medicine 2019 12(3):142-146 Objective: To investigate the potential role of wild birds as fecal spreaders of enteropathogenic, enterohemorrhagic and Shiga-toxins producing Escherichia coli (E. coli), enteropathogenic E. coli, enterohemorrhagic E. coli and Shiga toxin-producing E. coli strains. Methods: Fecal samples collected from 121 wild birds of different orders and species were submitted to molecular analyses. In particular, eaeA encoding intimin, hlyA encoding for hemolysin, stx1 and stx2 genes encoding Shiga-toxins 1 and 2, respectively, were investigated. Results: Overall, 21(17.35%) fecal samples resulted positive for at least one of the investigated genes. In detail, 12(9.91%) samples were positive for eaeA, 10(8.26%) for stx1, 4(3.31%) for hylA and 1(0.83%) for stx2. An owl (Athene noctua) positive for the four investigated genes suggesting that it harbored a STEC strain. However, virulence genes characterizing EPEC, and EHEC strains were mainly found among seagulls, waterfowl and feral pigeons. Conclusions: Seagulls, waterfowl and feral pigeons, which frequently reach and contaminate rural, urban and peri-urban areas with their droppings, may be important sources of E. coli infection for other animals and humans.