Background: Co-infection with malaria and intestinal parasites such asAscaris lumbricoidesis common. Malaria parasites induce a pro-inflammatory immune response that contributes to the pathogenic sequelae, such as malarial anaemia, that occur in malaria infection.Ascarisis known to create an anti-inflammatory immune environment which could, in theory, counteract the anti-malarial inflammatory immune response, minimizing the severity of malarial anaemia. This study examined whetherAscarisco-infection can minimize the severity of malarial anaemia.Methods: Data from a randomized controlled trial on the effect of antihelminthic treatment in Nigerian preschool-aged (6–59 months) children conducted in 2006–2007 were analysed to examine the effect of malaria andAscarisco-infection on anaemia severity. Children were enrolled and tested for malaria, helminths and anaemia at baseline, four, and eight months. Six hundred and ninety subjects were analysed in this study. Generalized linear mixed models were used to assess the relationship between infection status andAscarisandPlasmodiumparasite intensity on severity of anaemia, defined as a haemoglobin less than 11 g/dL.Results: Malaria prevalence ranged from 35-78% over the course of this study. Of the malaria-infected children, 55% were co-infected withAscarisat baseline, 60% were co-infected four months later and 48% were co-infected eight months later, underlining the persistent prevalence of malaria-nematode co-infections in this population. Over the course of the study the percentage of anaemic subjects in the population ranged between 84% at baseline and 77% at the eight-month time point. The odds of being anaemic were four to five times higher in children infected with malaria compared to those without malaria.Ascarisinfection alone did not increase the odds of being anaemic, indicating that malaria was the main cause of anaemia in this population. There was no significant difference in the severity of anaemia between children singly infected with malaria and co-infected with malaria andAscaris.Conclusion: In this cohort of Nigerian preschool children, malaria infection was the major contributor to anaemia status.Ascarisco-infection neither exacerbated nor ameliorated the severity of malarial anaemia.

Numerous studies have shown that anthelminthic treatment can be effective in improving growth rates when given to malnourished children with ascariasis. Recent investigations have also indicated that Ascaris infections can affect mental processing in some school children. Poor socio-economic conditions are among the key factors linked with higher prevalences of ascariasis, as are defaecation practices, geophagia, cultural differences relating to personal and food hygiene, occupational necessity, agricultural factors, housing style, social class and gender. Chemotherapy is currently the major tool used for the strategic control of ascariasis as a short-term goal. In the long term, improvements in hygiene and sanitation are thought to aid long-term control considerably. Targeted treatment, especially when aimed at schoolchildren, has been a major focus of recent control efforts in some areas. Universal treatment reaches more people and thus decreases further aggregate morbidity, especially in nutritionally vulnerable preschool-age children. Selective treatment requires technical effort to identify heavily infected individuals; acceptance by the community may vary in less educated populations when some individuals receive treatment and others do not. Child-targeted treatment may be more cost-effective than population treatment in reducing the number of disease cases and, in high transmission areas, expanding coverage of a population can be a more cost-effective strategy than increasing the frequency of treatment.

SUMMARY: Toxocaraspecies infect a wide range of companion, domestic and wild animals as definitive and paratenic hosts, via multiple routes of transmission, producing long-lived tissue-inhabiting larvae and resistant eggs that can survive in the external environment. ThereforeToxocaraand the disease it causes in humans, toxocariasis, represents an ideal aetiological agent for the development of the one health approach. However, despite increasing awareness of the public health significance of toxocariasis, gaps in our understanding of certain key aspects of the parasite's biology and epidemiology remain. These gaps hinder our ability to integrate research effort within the veterinary, medical and environmental disciplines. This review will highlight key deficits in our understanding of nine dimensions ofToxocaraepidemiology and discuss a potential scenario to develop a more integrated, one health approach to improve our understanding of the prevention and control of this complex and cryptic zoonosis.

Ocular toxocariasis in humans is typically a unilateral disease caused by second-stage larvae of the Toxocara species. Serological evidence of wides

SUMMARY: Ascaris lumbricoides, the human roundworm, is a remarkably infectious and persistent parasite. It is a member of the soil-transmitted helminths or geohelminths and infects in the order of 1472 million people worldwide. Despite, its high prevalence and wide distribution it remains along with its geohelminth counterparts, a neglected disease. Ascariasis is associated with both chronic and acute morbidity, particularly in growing children, and the level of morbidity assessed as disability-adjusted life years is about 10·5 million. Like other macroparasite infections, the frequency distribution ofA. lumbricoidesis aggregated or overdispersed with most hosts harbouring few or no worms and a small proportion harbouring very heavy infections. Furthermore, after chemotherapeutic treatment, individuals demonstrate consistency in the pattern of re-infection with ascariasis, described as predisposition. These epidemiological phenomena have been identified, in a consistent manner, from a range of geographical locations in both children and adults. However, what has proved to be much more refractory to investigation has been the mechanisms that contribute to the observed epidemiological patterns. Parallel observations utilizing human subjects and appropriate animal model systems are essential to our understanding of the mechanisms underlying susceptibility/resistance to ascariasis. Furthermore, these patterns ofAscarisintensity and re-infection have broader implications with respect to helminth control and interactions with other important bystander infections.

Outbred LACA mice were administered low (100 ova), medium (1000 ova), high (3000 ova) and trickle (4×250 ova) doses of Toxocara canis ova and the effect of infection was examined with respect to the number of larvae recovered from the brain and their behaviour. Recovery of larvae from the brain was generally low with the % recovery expressed in terms of the total dose administered being highest for the 3000 dose (6.1%) and 1000 dose (6%), followed by the 100 (4.4%) and trickle (3.5%) doses. The variation in larval recoveries was large between individual mice receiving similar doses. The level of infection in the brain was lower in mice receiving a multiple as opposed to an equivalent single dose of ova. Mice were then divided into three larval intensity groupings based upon the number of larvae recovered from their brain. The ranges for the groups were as follows: low intensity group, 0–15 larvae; moderate intensity group, 27–55 larvae; high intensity group, 66–557 larvae. Three behavioural tests were carried out on control and infected mice. Exploration and response to novelty was examined using a ‘T’ maze and learning was investigated by means of a water-finding task. Anxiety was measured using an elevated plus maze apparatus. Infected mice were less explorative and less responsive to novelty in the ‘T’ maze and this was particularly pronounced for the heavily infected mice. In the elevated plus maze, infected mice displayed reduced levels of anxiety to aversive and exposed areas of the maze, particularly in the case of the moderate and high intensity mice. There was evidence for impaired learning ability in the water task apparatus for moderate and high intensity mice. In general, the effects of infection on behaviour were more pronounced in the moderate and high intensity groups compared to the low intensity group.