Provider and household costs of Plasmodium vivax malaria episodes: a multicountry comparative analysis of primary trial data

OBJECTIVE

To determine household and health-care provider costs associated with Plasmodium vivax infection across a range of endemic settings.

METHODS

We collected cost data alongside three multicentre clinical trials of P. vivax treatment in Afghanistan, Brazil, Colombia, Ethiopia, Indonesia, Philippines, Peru, Thailand and Viet Nam conducted between April 2014 to December 2017. We derived household costs from trial participant surveys administered at enrolment and again 2 weeks later to determine the costs of treatment and transportation, and the number of days that patients and their household caregivers were unable to undertake their usual activities. We determined costs of routine care by health-care providers by micro-costing the resources used to diagnose and treat P. vivax at the study sites.

FINDINGS

The mean total household costs ranged from 8.7 United States dollars (US$; standard deviation, SD: 4.3) in Afghanistan to US$ 254.7 (SD: 148.4) in Colombia. Across all countries, productivity losses were the largest household cost component, resulting in mean indirect costs ranging from US$ 5.3 (SD: 3.0) to US$ 220.8 (SD: 158.40). The range of health-care provider costs for routine care was US$ 3.6-6.6. The cost of administering a glucose-6-phosphate-dehydrogenase rapid diagnostic test, ranged from US$ 0.9 to 13.5, consistently lower than the costs of the widely-used fluorescent spot test (US$ 6.3 to 17.4).

CONCLUSION

An episode of P. vivax malaria results in high costs to households. The costs of diagnosing and treating P. vivax are important inputs for future cost-effectiveness analyses to ensure optimal allocation of resources for malaria elimination.

Adaptive significance of male parental care in a monogamous mammal

Paternal behaviour presumably evolved because male care of young was critical for offspring survival. We report field evidence indicating that paternal behaviour enhances offspring survival in a monogamous mammal, the biparental California mouse, Peromyscus californicus. Male removal resulted in lower offspring survival in father-absent than in father-present families. New males took up residence with widowed females, but usually after females had stopped lactating, suggesting that the importance of the father is not primarily protection against infanticidal intruders but rather direct care of young.

Sex-biased mortality in woodrats occurs in the absence of parental intervention

Male-biased mortality in young animals is often viewed as adaptive discrimination against male offspring by parents unable to raise reproductively competitive sons. Unequivocal evidence of the presence or absence of parental discrimination against males is lacking, however, and the adaptive interpretation of male-biased mortality is confounded by an alternative explanation that it reflects differential energetic requirements between the sexes (due to sexual selection for large size in mature males) independent of parental manipulation. To determine whether maternal discrimination against offspring explains postnatal mortality in a sexually dimorphic rodent, we examined patterns of growth and mortality in offspring of food-restricted and food-enriched lactating bushy-tailed woodrats, Neotoma cinerea. We also monitored mothers and their litters daily throughout lactation for evidence of maternal discrimination against offspring. Offspring of food-restricted mothers showed depressed growth, and mortality of offspring born to both food-restricted and food-enriched mothers was male-biased, but in the absence of maternal discrimination. Offspring that died were no less likely to be attached to their mother's teats in the 10 days prior to death than were offspring that successfully weaned. Similarly, offspring of food-restricted mothers were attached as often as were offspring of food-enriched mothers. In a series of behavioural arena trials in the first 10 days after birth, restricted mothers were no less attentive toward their sons than they were to their daughters, nor did mothers treat their offspring that did not survive to weaning differently from those that survived. Our findings provide empirical evidence that postnatal, sex-biased mortality in offspring is not necessarily due to parental intervention, and they call into question the adaptive interpretations of previous examples of sex-biased offspring mortality. Copyright 1998 The Association for the Study of Animal Behaviour Copyright 1998 The Association for the Study of Animal Behaviour.

Littoral feeding in a high-density insular population of Sorex cinereus

In a high-density insular population of masked shrews (Sorex cinereus), Diptera, amphipods, Araneae, and Coleoptera dominated the diet. The prominence of littoral amphipods and kelp flies in the diet indicates a pattern of beach foraging not previously described for this shrew. Remains of these prey were found in shrews captured as far as 60 m inland. We speculate that abundant littoral invertebrate prey, present throughout much of the year, partly sustain the high number and extended breeding season of shrews on this island.