Freshwater snails of the genus Biomphalaria, Preston 1910, are the most important and widely distributed intermediate hosts of Schistosoma mansoni, the blood fluke responsible for human intestinal schistosomiasis, in Africa and the Neotropics. S. mansoni is thought to have been imported repeatedly into the Americas during the last 500 years with the African slave trade. Surprisingly considering that the New and Old World separated 95-106 million years (Myr) ago, the disease rapidly became established due to the presence of endemic susceptible hosts. Reconstructing the phylogenetic relationships within Biomphalaria may provide insights into the successful intercontinental spread of S. mansoni. Parsimony and distance analyses of mitochondrial and nuclear sequences show African taxa to be monophyletic and Neotropical species paraphyletic, with Biomphalaria glabrata forming a separate clade from other Neotropical Biomphalaria, and ancestral to the African taxa. A west to east trans-Atlantic dispersal of a B. glabrata-like taxon, possibly as recently as the Plio-Pleistocene (1.8-3.6 Myr ago) according to a general mitochondrial clock, would fit these observations. Vicariance or an African origin for B. glabrata followed by multiple introductions to South America over the past 500 years with the African slave trade seem unlikely explanations. Knowledge of the phylogenetic relationships among important intermediate host species may prove useful in furthering control measures which exploit genetic differences in susceptibility to parasites, and in elucidating the evolution of schistosome resistance.

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Aim To document the clinical features and management of infants presenting with fever after their first meningococcal B vaccination and develop guidance for clinicians. Methods A prospective case series over 12 months was conducted in a tertiary paediatric hospital. Infants ≤3 months of age with fever who had received their first set of immunisations within the preceding 72 h were included. Results A total of 92 infants met the inclusion criteria, accounting for 0.78% of the local vaccinated population. The most commonly described associated features were poor feeding, sleepiness and irritability; 66 patients (72%) were admitted to hospital. Median C‐reactive protein (CRP) was 12 mg/L, and median white cell count (WCC) was 16 × 109/L. Fifteen patients (16%) had a lumbar puncture and were commenced on antibiotics. There was one confirmed bacterial infection in an infant who had presented with fever starting 54 h after immunisation. All other microbiology samples were negative. There were no cases of missed serious bacterial infection (SBI) in those patients who were observed or discharged. Conclusions The routine investigation of infants presenting with post‐immunisation fever is not warranted if the infant appears otherwise well on examination. Where other common associated features are present or there is clinical concern, a period of observation is a prudent course of action. Paracetamol should be given peri‐immunisation as per the national guidance. We suggest selective use of investigations, especially inflammatory markers, which are unlikely to discriminate between SBI and post‐immunisation response. We advocate extra caution in infants presenting with fever more than 48 h after immunisation.