Diversity of Biomphalaria spp. freshwater snails and associated mollusks in areas with schistosomiasis risk, using molecular and spatial analysis tools

Abstract

The Middle Paranapanema River region of São Paulo, Brazil is home to significant diversity of Biomphalaria species and is very vulnerable to health and environmental impacts such as schistosomiasis. This study updates freshwater malacological surveys for ecosystems in one portion of the Middle Paranapanema River Basin, with emphasis on the genus Biomphalaria. Snails were collected from 114 distinct bodies of water between 2015 and 2018. Biomphalaria specimens were identified according to morphological and molecular characteristics, while animals in other genera (Drepanotrema, Lymnaea, Melanoides, Physa and Pomacea) were identified solely according to shell characteristics. A geographic information system was used to update intermediate host colonization sites and consequently assist in identifying probable hotspots for intermediate hosts of schistosomiasis. The sequences of the COI gene relating to the DNA barcode stretch were tested for similarity against sequences found in GenBank, for monophyly through Maximum Likelihood phylogenetic inference, and analyzed in ABDG, bPTP and GMYC for the delimitation of putative species. Of the 10,722 snails collected, 86.7% were in the Planorbidae family (75.5% Biomphalaria and 11.2% Drepanotrema) and 13.3% were other non-Planorbidae species (Lymnaea, Melanoides, Physa and Pomacea). The taxonomic COI reference sequences in the NCBI nucleotide database used for DNA sequence comparison, and phylogenetic analysis used to test the monophyly of the groups, resulted in more reliable taxonomic units than delimitation of the COI sequences in MOTUs using statistical taxonomic models. Analysis of the species distribution shows that B. glabrata and B. tenagophila are heterogeneously distributed in the study area. B. glabrata colonizes only five water bodies, in the study area, most of them in Ourinhos, while B. tenagophila predominates in water bodies in Ipaussu. Contrasting with this, B. straminea, B. occidentalis and B. peregrina are evenly distributed throughout the study area.

Geographic Information System-based association between the sewage network, geographical location of intermediate hosts, and autochthonous cases for the estimation of risk areas of schistosomiasis infection in Ourinhos, São Paulo, Brazil

“…The numbers (N°) in Figure 1 C correspond to the collection points presented in Table 1 . Source: IBGE 36 , 37 ; SMA 38 ; SUCEN/Palasio et al 14 ; SINAN/CVE. …”

“…The schistosomiasis cases observed in Ourinhos are probably associated with B. glabrata , which is a natural host to S. mansoni in the municipality 10 , 11 . This species was initially identified in Ourinhos in 1919 12 and continues to proliferate in water bodies in this municipality 13 , 14 . B. tenagophila and B. straminea, two other S. mansoni intermediate-host (IH) species, have also been described/observed in the area 13 , 14 .…”

“…This species was initially identified in Ourinhos in 1919 12 and continues to proliferate in water bodies in this municipality 13 , 14 . B. tenagophila and B. straminea, two other S. mansoni intermediate-host (IH) species, have also been described/observed in the area 13 , 14 .…”

Taxonomic diversity of Biomphalaria (Planorbidae) in São Paulo state, Brazil

“…Biomphalaria straminea is the main intermediate host for S. mansoni in the northeast of Brazil (Figueiredo 1989, Ohlweiler et al 2010. Its high capacity to spread through new water collections (Pointier et al 2005, Palasio et al 2019) may facilitate the expansion of the species in the state of São Paulo. This poses a challenge to control the disease, which requires monitoring and constant mapping of water bodies and the snails associated with them.…”

A Cross Sectional Assessment on Distribution of Snail and Risk Factors of Schistosoma Mansoni Infection in Proximity to Water Contact Points in Gorgora Town, Western Dembia District, Northwest Ethiopia.

“…In Mecha North West Ethiopia, 46.1% Helix, 23.7% Lymnaea, 13.2% Bulinus, 9.2% Planorbin, and 7.9% Oncomelania (40) was reported. In Middle Paranapanema River region of São Paulo, Brazil, of the 10,722 snails collected, 86.7% were in the Planorbidae family (75.5% Biomphalaria and 11.2% Drepanotrema) and 13.3% were other non-Planorbidae species (Lymnaea, Melanoides, Physa and Pomacea)(41). This variation might be due to seasonality of snail abundance and freshwater snails are generally encountered in freshwater body that is polluted with human and animal excreta.On the other hand, this nding was in contrast when compared to studies carried out in Kisumu City, western Kenya, which reported out of 1,059 snails collected, 407 (38.4%) were putatively identi ed as B. sudanica,425(40.1%) as B. pfeifferi and 227(21.5%) as Bulinus globosus(42).…”