Plant collecting spread and densities: their potential impact on biogeographical studies in Thailand

Aims To produce representative aggregate maps of plant collection locations in Thailand and discuss their impact on biogeographical studies in Thailand and the surrounding region. Location Thailand. Methods A representative data set comprising 6593 plant specimen records for Thailand has been assembled. The data set contains ± all known collections for fifteen representative plant families and further records for another 104. All records are localized to Changwat (province), 6441 to at least quarter degree square. Results Analysis shows that the spread of collecting activity in Thailand is markedly uneven; 20% of collections come from a single Changwat (Chiang Mai) and 53% of Changwat have fifty or fewer collections. The distribution of collections by Changwat and by quarter degree square is erratic with most squares and Changwat having few collections, both in proportionate and absolute terms. Some of the most densely forested Changwats and squares appear undercollected. Distribution maps for common, easily recognized tree species in the genus Syzygium show distributional gaps. Conclusions Thailand is defined as an undercollected country. Even within the few well‐collected quarter degree squares the spread of collecting is still poor; almost all collections being localized to one of three mountain ranges or their foothills. There are many gaps in collecting activity which make impossible a straightforward interpretation of biogeographical pattern. It is argued that targeted collecting activity is needed, that assembly of this type of data set is therefore essential and that our data set and its interpretation is a model for all countries in the region.     

Taxonomic notes on the genus Piper (Piperaceae)

Sixteen lectotypifications of Asian Piper species are provided. Piper argyrites, P. baccatum, P. leptostachyum, P. majusculum, P. peepuloides, P. quinqueangulatum and P. sulcatum are accepted as species and many new synonyms are proposed. Useful diagnostic characters are described and geographical distribution data of each species are provided.     

Directly observed therapy and improved tuberculosis treatment outcomes in Thailand

Background

The World Health Organization (WHO) recommends that tuberculosis (TB) patients receive directly observed therapy (DOT). Randomized controlled trials have not consistently shown that this practice improves TB treatment success rates. In Thailand, one of 22 WHO-designated high burden TB countries, patients may have TB treatment observed by a health care worker (HCW), family member, or no one. We studied whether DOT improved TB treatment outcomes in a prospective, observational cohort.

Methods and Findings

We prospectively collected epidemiologic data about TB patients treated at public and private facilities in four provinces in Thailand and the national infectious diseases hospital from 2004–2006. Public health staff recorded the type of observed therapy that patients received during the first two months of TB treatment. We limited our analysis to pulmonary TB patients never previously treated for TB and not known to have multidrug-resistant TB. We analyzed the proportion of patients still on treatment at the end of two months and with treatment success at the end of treatment according to DOT type. We used propensity score analysis to control for factors associated with DOT and treatment outcome. Of 8,031 patients eligible for analysis, 24% received HCW DOT, 59% family DOT, and 18% self-administered therapy (SAT). Smear-positive TB was diagnosed in 63%, and 21% were HIV-infected. Of patients either on treatment or that defaulted at two months, 1601/1636 (98%) patients that received HCW DOT remained on treatment at two months compared with 1096/1268 (86%) patients that received SAT (adjusted OR [aOR] 3.8; 95% confidence interval [CI] 2.4–6.0) and 3782/3987 (95%) patients that received family DOT (aOR 2.1; CI, 1.4–3.1). Of patients that had treatment success or that defaulted at the end of treatment, 1369/1477 (93%) patients that received HCW DOT completed treatment compared with 744/1074 (69%) patients that received SAT (aOR 3.3; CI, 2.4–4.5) and 3130/3529 (89%) patients that received family DOT (aOR 1.5; 1.2–1.9). The benefit of HCW DOT compared with SAT was similar, but smaller, when comparing patients with treatment success to those with death, default, or failure.

Conclusions

In Thailand, two months of DOT was associated with lower odds of default during treatment. The magnitude of benefit was greater for DOT provided by a HCW compared with a family member. Thailand should consider increasing its use of HCW DOT during TB treatment.     

Pogostemon nudus sp. nov. (Lamiaceae) from Thailand

A new species of Pogostemon Desf., P. nudus Bongcheewin & Pramali, is described, illustrated and compared with the similar P. menthoides from Thailand. Morphological characters, especially the micromorphology of nutlets and leaf epidermis, and conservation status in accordance with the IUCN red list categories and criteria are described and discussed. In addition, a key to all species of P. sect. Pogostemon known from Thailand is presented.     

Development of species-specific SCAR markers for identification of three medicinal species of Phyllanthus

Phyllanthus amarus Schum. & Thonn. has been widely used in traditional medicine in Thailand as an antipyretic, a diuretic, to treat liver diseases and viral infections. Two closely related species, P. debilis L. and P. urinaria Klein ex Willd., with different and less effective medicinal properties, are less commonly used. These three species are similar in morphology and often occur in overlapping populations in nature. The latter two species can easily be mistaken for P. amarus and collected for medicinal uses, which can lead to undesirable results. DNA fingerprints of these species were obtained using RAPD-PCR techniques. RAPD markers specific for each species were identified. Primers for highly specific sequence-characterized-amplified-regions (SCAR) were then designed from nucleotide sequences of specific RAPD markers. These primers efficiently amplified SCAR markers of 408, 501 and 319 bp unique to P. amarus, P. debilis and P. urinaria respectively. This method of plant identification was rapid and highly specific when tested against DNA of several closely related species and was able to amplify specific markers from mixed DNA samples.