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Background Foodborne infections caused by lung flukes of the genus Paragonimus are a significant and widespread public health problem in tropical areas. Approximately 50 Paragonimus species have been reported to infect animals and humans, but Paragonimus westermani is responsible for the bulk of human disease. Despite their medical and economic importance, no genome sequence for any Paragonimus species is available. Results We sequenced and assembled the genome of P. westermani, which is among the largest of the known pathogen genomes with an estimated size of 1.1 Gb. A 922.8 Mb genome assembly was generated from Illumina and Pacific Biosciences (PacBio) sequence data, covering 84% of the estimated genome size. The genome has a high proportion (45%) of repeat-derived DNA, particularly of the long interspersed element and long terminal repeat subtypes, and the expansion of these elements may explain some of the large size. We predicted 12,852 protein coding genes, showing a high level of conservation with related trematode species. The majority of proteins (80%) had homologs in the human liver fluke Opisthorchis viverrini, with an average sequence identity of 64.1%. Assembly of the P. westermani mitochondrial genome from long PacBio reads resulted in a single high-quality circularized 20.6 kb contig. The contig harbored a 6.9 kb region of non-coding repetitive DNA comprised of three distinct repeat units. Our results suggest that the region is highly polymorphic in P. westermani, possibly even within single worm isolates. Conclusions The generated assembly represents the first Paragonimus genome sequence and will facilitate future molecular studies of this important, but neglected, parasite group.

In the northeastern region of India, paragonimiasis is emerging as an important public health problem. However, until now the identity of the species causing human infection has been uncertain and there has been little information on the prevalence and clinicoradiological features of infection in the community. Parasitological and immunological surveys revealed that paragonimiasis was hyperendemic in parts of Arunachal Pradesh. Egg positivity in the sputum was 20.9% and 4.1% in children (age/=15 years) and adults (age15 years), respectively. Antibody positivity against excretory-secretory antigen of the adult worm in children and adults was 51.7% and 18.7%, respectively. Chronic cough (97.2%) and haemoptysis (83.3%) were common respiratory symptoms among egg-positive cases. Chest radiography (n=68) images from egg-positive cases showed that air space consolidation (75%), cavitary lesions (14.7%) and mediastinal adenopathy (11.8%) were very frequent. Less frequent findings were nodular lesions, bronchiectasis, mediastinal adenopathy, pleural thickening and pleural effusion. DNA extracted from eggs from the sputum of patients from Arunachal Pradesh was sequenced. Analyses of the second internal transcribed spacer (ITS2) of nuclear rDNA revealed that the species responsible is Paragonimus heterotremus.

A four-arm drug sensitivity study compared chloroquine, sulfadoxine-pyrimethamine (SP), mefloquine and mefloquine-artesunate in Sonitpur and Karbi Anglong districts in Assam state, India. Two criteria were used to ascertain outcome: success of clinical treatment and parasitologic cure. In Sonitpur, at 14 days, there were 36/56 early and late treatment failures plus late parasitologic failures to chloroquine and 16/56 for SP. In Karbi Anglong, combined treatment failure at 14 days was 16/56 to chloroquine and 8/60 to SP. Mefloquine and mefloquine-artesunate demonstrated 93.9% and 93.6% sustained responses respectively at 42 days. High failure rates to both chloroquine and SP preclude the use of these drugs as first-line treatment for uncomplicated falciparum malaria in this region. A mefloquine-artesunate combination presents an effective alternative utilizing the currently recommended higher dose of mefloquine.