Genetic variability of Haemonchus contortus isolates in small ruminants from slaughterhouses in Bangladesh.

Haemonchus contortus is a blood-sucking gastrointestinal nematode that infects all ruminants and causes significant economic losses in production. Characterizing the genetic variability of H. contortus populations is crucial for understanding patterns of disease transmission and developing effective control strategies against haemonchosis. This study aimed to identify the genetic variability of H. contortus isolates in small ruminants from slaughterhouses in Bangladesh. During January to December 2015, 400 abomasa samples were collected and 186 were found to be positive for Haemonchus. A 321-bp fragment of the second internal transcribed spacer (ITS-2) of nuclear ribosomal DNA and an 800-bp fragment of the mitochondrial nicotinamide dehydrogenase subunit-4 gene (nad4) were amplified using polymerase chain reaction (PCR) and directly sequenced. The results showed 10 genotypes (ITS-2) and 45 haplotypes (nad4) among the 186 worms. The sequences were 98.5 to 100% identical to reference sequences from the GenBank database. ITS-2 sequence analysis revealed four nucleotide substitutions at positions 30, 41, 42, and 216. There was one transition (C/T) at position 42 and three transversions (C/A at position 30, G/C at position 41, and T/A at position 216). The nad4 gene sequences showed 15 substitutions, all of which were transitions. The pairwise distance of ITS-2 between H. contortus populations ranged from 0.005 to 1.477. The nucleotide diversity (µ) among the populations was 0.009524 using ITS-2 and 0.00394 using nad4. This study indicated low genetic deviation among H. contortus populations in Bangladesh.

Screening of a library of traditional Chinese medicines to identify anti-malarial compounds and extracts.

BACKGROUND: Malaria is a major infectious disease in the world. In 2015, approximately 212 million people were infected and 429,000 people were killed by this disease. Plasmodium falciparum, which causes falciparum malaria, is becoming resistant to artemisinin (ART) in Southeast Asia; therefore, new anti-malarial drugs are urgently needed. Some excellent anti-malarial drugs, such as quinine or ART, were originally obtained from natural plants. Hence, the authors screened a natural product library comprising traditional Chinese medicines (TCMs) to identify compounds/extracts with anti-malarial effects. METHODS: The authors performed three assays: a malaria growth inhibition assay (GIA), a cytotoxicity assay, and a malaria stage-specific GIA. The malaria GIA revealed the anti-malarial ability and half-maximal inhibitory concentrations (IC50) of the natural products, whereas the malaria stage-specific GIA revealed the point in the malaria life cycle where the products exerted their anti-malarial effects. The toxicity of the products to the host cells was evaluated with the cytotoxicity assay. RESULTS: Four natural compounds (berberine chloride, coptisine chloride, palmatine chloride, and dehydrocorydaline nitrate) showed strong anti-malarial effects (IC50 < 50 nM), and low cytotoxicity (cell viability > 90%) using P. falciparum 3D7 strain. Two natural extracts (Phellodendri cortex and Coptidis rhizoma) also showed strong antiplasmodial effects (IC50 < 1 µg/ml), and low cytotoxicity (cell viability > 80%). These natural products also demonstrated anti-malarial capability during the trophozoite and schizont stages of the malaria life cycle. CONCLUSIONS: The authors identified four compounds (berberine chloride, coptisine chloride, palmatine chloride, and dehydrocorydaline nitrate) and two extracts (Phellodendri cortex and Coptidis rhizoma) with anti-malarial activity, neither of which had previously been described. The IC50 values of the compounds were comparable to that of chloroquine and better than that of pyrimethamine. These compounds and extracts derived from TCMs thus show promise as potential future anti-malarial drugs.