Feeding Problems and Oropharyngeal Dysphagia in Children

Pamela Dodrill

Pamela Dodrill, Specialist Speech Pathologist, Health Research Fellow, Royal Children’s Hospital, Herston Rd, Herston, Brisbane 4029, Queensland, Australia

Correspondence to: Pamela Dodrill, Specialist Speech Pathologist, Health Research Fellow, Royal Children’s Hospital, Herston Rd, Herston, Brisbane 4029, Queensland, Australia
Email: pamela_dodrill@health.qld.gov.au
Received: January 31, 2014
Revised: April 25, 2014
Accepted: April 28, 2014
Published online: May 21, 2014


Like adults, infants and older children can present with swallowing and feeding difficulties. Unlike adults, children have rapidly developing body systems, and even short-term problems with swallowing and/or feeding can interrupt normal development and cause serious long-term sequelae. In order for a child to reach their physical and cognitive growth potential, sufficient energy and nutrients must be consumed. Feeding difficulties can have a detrimental effect on dietary intake and, hence, growth. This article aims to provide an overview of the typical development of feeding skills in children, as well as of interventions aimed at assisting children with feeding and swallowing difficulties. A review of the literature indicates that many intervention techniques utilized by clinicians have not been formally evaluated by high-quality research studies and, thus, further research in this area is needed to support and guide clinical practice.

Key words: Children; Feeding; Dysphagia

© 2014 The Author. Published by ACT Publishing Group Ltd.

Dodrill P. Feeding Problems and Oropharyngeal Dysphagia in Children. Journal of Gastroenterology and Hepatology Research 2014; 3(5): 1055-1060 Available from: URL: http://www.ghrnet.org/index.php/joghr/article/view/694


Feeding skills undergo a period of rapid development throughout the first year of life. During the first months after birth, an infant’s nutritional needs are met by a diet of breast milk or infant formula. Later on in infancy, solid foods are introduced to supplement milk feeds. The transition from a liquid-based diet to a diet consisting of solids and liquids is an important developmental process that allows infants to consume a larger volume and variety of nutrients, which is important in meeting their expanding dietary requirements as they grow[1-3]. From birth to 12 months of age, healthy infants generally experience a 50% increase in their length and a 200% increase in their weight[3]. Clinically, a child’s growth is used as a crude indicator of their nutritional intake and feeding skills, such that, if they are growing well, it would generally be assumed that their dietary intake must be sufficient to meet their nutritional requirements and, if fully orally fed, that their feeding skills are sufficient to allow them to consume the required nutrition[4,5].

During infancy, a child progresses from being fully dependent on a feeder, through a period of semi-dependence, where they begin to take on some responsibility and make some choices related to feeding[6,7]. Later still, children learn to feed themselves with complete independence. Early neurological development allows the transition from brainstem-mediated suckling reflexes to voluntary oral movements during eating, which require higher cortical input[6-8]. Anatomical changes result in an enlarged oral cavity, allowing more space for food to be manipulated within the mouth[6,7]. In addition, developmental gains in the area of gross motor skills allow the infant to sit upright with decreasing amounts of support, and to commence self-feeding.

In order for an infant to feed competently during the suckling period, they need to display functional suckling and swallowing skills, as well as the ability to coordinate suckling, swallowing, and breathing. Later, during the transitional feeding period, infants also need to learn to competently chew and bite, so that they can safely consume solid foods of more challenging textures. Increasing levels of oral-motor skill are required to progress from breastfeeding/ bottle feeding onto beginner (pureed) solid foods that are taken from a spoon, and then on to mashed and soft solid pieces that can be broken down with the tongue, and later soft- and hard-mechanical food textures that require chewing +/- biting (Table 1)[7,9]. Increasing oral-motor skills are also required to move from drinking from the breast/ bottle onto drinking via a spout or straw cup and then an open cup[7].

Infants generally begin weaning onto solid foods at the same time that they begin to be able to sit in an upright position and bring their hands to their mouth. Postural support is an important pre-requisite for the introduction of solids, as gross motor control of the trunk and neck is needed to support the fine motor skills involved in chewing and biting[6,7]. As infants mature, their trunk control, neck control, and jaw control all mature in a sequential process[6,7]. Supportive seating, as well as manipulation of the size and firmness of food pieces offered by the caregiver, assists to maximise the child’s ability to eat efficiently and safely[9].

Newborns require full postural support during feeds. From birth to 4 months of age, infants diet consists entirely of fluid, taken in the form of breastfeeds or bottle feeds[1,2]. Young infants rely on adaptive oral reflexes (i.e. rooting and suckling) to locate and ingest feeds, and display a forward-backward tongue pattern while feeding[6,7]. Young infants are unable to consume or effectively digest any solid foods[1,2], and display protective oral reflexes (e.g. tongue protrusion, phasic bite, and strong gag reflexes) to protect the airway[6,7].

At 4 months of age, most infants are still only consuming fluids (as either breastfeeds or bottle feeds). However, from 4-6 months infants begin to display separation of tongue and jaw movements, and transition from a reflexive suckle (forward-backwards) to a suck (up-down) tongue pattern while feeding[6,7]. During this time, infants begin to be able to sit more upright, but still require full postural support (e.g. seated in a baby chair with straps, or on the feeder’s lap with the feeder’s arm supporting the head and trunk)[7]. Most infants will begin to bring their hands to their mouth at this stage for oral self-exploration. This helps to desensitise some of the protective reflexes (e.g. tongue protrusion) and, toward the end of this period, many infants will begin to consume beginner (i.e. pureed) solids from a spoon (Table 1).

At 7-9 months of age, the infant diet still consists mostly of fluids, but infants are able to consume a greater volume and variety of solid foods[1,2]. Infants continue to consume fluids from the breast or bottle, but many begin to be able to drink from a cup[6,7]. As infants develop the core stability to sit up with less external support, and as many of the protective oral reflexes diminish and/or are integrated into more sophisticated, voluntary oral skills (e.g. phasic bite transitions to chewing)[7], infants can begin to consume mashed solids and small pieces of soft foods (Table 1). As hand-to-mouth coordination improves, most infants begin some (messy) self-feeding[7], however, much assistance from caregivers is still required during mealtimes at this age.

At 9-12 months of age, infants are generally consuming a mixed diet of fluids and solids. During the day, an increasing proportion of fluids may be taken from a cup, though infants still require breastfeeds or bottle feeds to meet their nutritional requirements[1,2]. Most infants can sit without support at this age, and most are beginning to stand and walk. However, the majotiry of infants continue to be fed in a baby chair or on a caregiver’s lap, in order to provide postural support while they continue to develop their fine motor skills[7]. Self-feeding is more common at this age, and improved jaw stability and tongue lateralisation skills allow infants to bite and chew soft-mechanical foods (Table 1)[7,9].

From 12-24 months of age, toddlers’ oral feeding skills continue to improve and become more refined and coordinated, which results in improved efficiency of mealtimes and a greater variety of foods consumed. Children gradually learn to bite through hard-mechanical foods (Table 1)[9] during this period. Toddlers also become more competent at using utensils to assist with eating. This process occurs in parallel with improvements in general motor development and sensory integration (the neurological process that organises sensations from the environment and one’s own body, such as sight, smell, touch, taste, and proprioception, to allow a functional response), as well as with maturation of cognitive processes[6,7]. Toddlers continue to require assistance from their caregivers in offering appropriate foods in manageable size portions, and should be supervised while eating any foods that pose a choking risk[9].


Given the inter-relationship between anatomical and neurological maturation in early development, as well as between sensory, motor, and cognitive development, there is a potential for difficulties to occur if any or all of these processes are interrupted during the developmental process[6,7].

By virtue of their premature delivery, early development is interrupted in preterm infants. Premature exposure to the ex-utero environment forces preterm infants to breathe and feed for themselves at a time when oxygen and nutrients would have been provided to them by the placenta had they remained in utero. In addition, preterm infants are forced to support their body against the effects of gravity, rather than have the support of amniotic fluid and the uterine wall around them. Further, either as a direct result of their premature birth or as a coinciding event, many preterm infants present with severe co-morbidities[10,12]. Both the impairments themselves, as well as the interventions required to treat them, have the potential to further interrupt feeding development in these infants[10,11,12]. In addition, prolonged hospitalisation (and the resulting frequent exposure to hospital lights, alarms, and painful procedures) can interfere with the infant’s sensory development, and can affect the family’s ability to interact and bond with their child[10,11].

A summary of some of the possible interruptions to early oral feeding development commonly cited as being associated with illness and medical treatment is included in table 2[6,7].

Table 3 contains a list of conditions that are commonly associated with feeding difficulties[7,8,12]. It should be noted that some of these conditions have the potential to impact on oral feeding directly (i.e. they may affect sucking strength, suck-swallow-breath coordination, or the ability to bite and chew effectively), and others impact on oral feeding indirectly (i.e. they may not directly impact on the oral or pharyngeal phases of swallowing, but may cause pain, discomfort, or fatigue with feeds, or limit the volume the child can consume by mouth). However, during the period of time when young children are developing their oral feeding skills, any feeding disturbances can potentially impact on later feeding skills through interruption of the normal developmental process[6,7].

Often, prematurity and/or chronic, ongoing illness can result in periods of time where infants cannot feed by mouth. Then, even once an infant is well enough and mature enough to attempt oral feeds, it may be some time before their feeding skills have developed enough to support independent oral feeding[6,7,11,12]. During the period of time when medically complex infants are unable to feed exclusively by mouth, they will require some form of artificial tube feeding to meet their energy, nutrition, and fluid requirements[4,5].

As discussed in table 2, in the short term, tube feeding (as well as other invasive procedures that occur in and around the mouth, such as suctioning and intubation) may cause obstruction and/or irritation of the structures involved in feeding[13-41]. In the longer term, the iatrogenic effects of medical interventions affecting the mouth and associated structures, as well as a lack of oral feeding practice, may contribute to the development of altered oral sensitivity and/or oral aversion, as well as inefficient feeding patterns[27-35,38-40]. In addition, any coinciding developmental delays in motor skills or alterations to muscle tone may result in poor postural support and reduced control of the muscles of the mouth involved in oral feeding[7,11]. Further, due to the effects of prematurity and/or illness, many medically complex infants will display poor nutritional and energy reserves, which may result in low endurance levels for the work of feeding[11].


During normal swallowing, the bolus is propelled from the oral cavity through the pharynx and down the oesophagus. At the same time, the vocal folds close and a brief deglutition apnoea occurs, along with superior and anterior laryngeal excursion[6,42]. This helps to ensure that the bolus ends up in the gut and not in the airway. Dysphagia occurs when there is a problem with bolus containment and/or propulsion, and may occur at the oral, pharyngeal, and/or oesophageal phases of swallowing[6,42]. A prolonged apnoea event occurs when the airway closes over and fails to re-open in time for regular breathing to continue after a swallow[43,44]. Airway penetration occurs when the bolus (liquid or solid) enters the laryngeal vestibule. Aspiration occurs when the bolus enters the airway below the level of the vocal folds[42]. Choking occurs when a solid bolus physically blocks the airway[6].

Mealtime behaviour disturbances or food/ fluid aversion commonly arise in association with dysphagia, aspiration, or a choking event[6,7]. At other times, there is no apparent physical reason for behavioural feeding issues, although aversive experiences in or around the mouth (e.g. tube feeding, suctioning), undetected pain (e.g. as associated with tonsillitis, pharyngitis, or teething), or sensory disturbances (e.g. oral hypersensitivity) are usually involved at some level[6,7].


Interventions for feeding and/or swallowing difficulties need to be targeted at the cause/s of the problem in order to be effective. For this reason, a thorough assessment is required to guide any intervention offered. Paediatric feeding assessments generally involve assessment across a number of different developmental areas that have the potential to impact of feeding[6,7], and these are detailed in table 4. Once the nature and any possible factors contributing to the feeding/ swallowing difficulty have been established, the treatment plan can be developed.

It is widely accepted that interdisciplinary team management of feeding and swallowing difficulties is desirable, involving members from various medical specialties, nursing, dietetics, and developmental therapies (i.e. speech pathology, occupational therapy, physical therapy, and psychology), as appropriate, working together to manage the various components of the problem. In addition, it is also widely recognised that it is essential to have parent involvement in assessment, setting therapy goals, delivering therapy, and monitoring progress, to ensure that any intervention is meaningful for the child and family, and to assist with the generalization of therapy gains to the home environment.

For children with oral phase swallowing problems, a review of the literature suggests that treatment generally involves working on improving the sensory and/or motor skills required for drinking and eating[6,7,45-47]. While commonly used in clinical practice, there are only a few small, randomised controlled trials evaluating these techniques in young preterm infants[45-47]. A recent Cochrane systematic review investigating the use of oral sensori-motor techniques in older children with dysphagia related to neurological problems[48] found that there is currently insufficient high-quality evidence from randomized controlled trials to provide conclusive results about the effectiveness of any particular type of therapy technique for children in this population and, thus, further research is required to evaluate these treatment strategies.

For children with swallowing problems affecting the pharyngeal phase, a literature review suggests that treatment generally involves teaching the child to modify their swallowing strategy or for the feeder to modify the bolus[6,7,42,49,50]. A summary of interventions used with infants with poor suck-swallow-breath coordination and older children with poor swallowing and breathing coordination is detailed in table 5 and 6. A few small studies have reported these strategies to be effective in improving physiological stability during feeds and improving volume of intake in young in preterm infants[49,50], though no randomised controlled trials have been conducted. Further research is required to evaluate the effectiveness of treatment strategies in both infants and older children.

For children with mealtime behaviour disturbances or food/ fluid aversion, therapy is usually either based on the principles of operant conditioning (clinician-driven, top-down, prompt-and-reward therapy) or systematic desensitization (child-driven, bottom-up, play-based therapy). A few small studies have reported that behavioural treatment based on operant conditioning is effective in children with Autism Spectrum Disorder (ASD)[51,52,53], though no randomised controlled trials have been conducted to date. Further research is required to evaluate the effectiveness of behavioural treatments for other groups of children with feeding difficulties, as well as to evaluate the relative effectiveness of different behavioural feeding approaches.


Feeding skills undergo a period of rapid development throughout early childhood, alongside general development and growth. Safe and efficient feeding and swallowing skills are important to allow children to meet their expanding dietary requirements as they grow. In a developing system, even short-term problems with swallowing and/or feeding can interrupt normal development and have serious long-term sequelae. This article provides an overview of normal feeding development in children, as well as of interventions aimed at assisting children with feeding and swallowing difficulties. The importance of a thorough assessment to guide intervention is highlighted. A review of the current evidence-base demonstrates that many intervention techniques utilized by clinicians have not been formally evaluated in the literature and, thus, further research is needed to support and guide clinical practice.


There are no conflicts of interest with regard to the present study.


1 World Health Organisation (2013). Global Strategy for Infant and Young Child Feeding. Geneva

2 National Health and Medical Research Council (2012) Infant Feeding Guidelines. Canberra: National Health and Medical Research council

3 Centers for Disease Control. Growth Charts for Infants: http://www.cdc.gov/growthcharts/

4 Gomella TL, Cunningham MD, Eyal FG, Zenk KE. Neonatology: Management, procedures, on-call problems, diseases, and drugs. 5th Ed. New York: The McGraw-Hill Companies, Inc; 2004

5 Behrman R, Kliegman R, Jenson H. Nelson Textbook of Pediatrics. 17th Ed. Philadelphia: Saunders; 2004.

6 Arvedson JC, Brodsky L. Pediatric Swallowing and Feeding: Assessment and management. 2nd Ed. Albany, NY: Singular Thomson Learning; 2002

7 Morris SE, Klein MD. Pre-Feeding Skills: A comprehensive resource for feeding development. 2nd Ed. Arizona: Therapy Skill Builders; 2000

8 Wilson-Pauwels L, Akesson EJ, Stewart PA, Spacey SD. Cranial Nerves In Health and Disease. 2nd Ed. Hamilton, Ontario: BC Decker Inc; 2002

9 Dietitians Association of Australia and The Speech Pathology Association of Australia Limited (2007). Texture-modified foods and thickened fluids as used for individuals with dysphagia: Australian standardised labels and definitions. Nutrition & Dietetics 2007; 64: S53–S76

10 McGrath JM, Kenner C, Amspacher KA. Factors that can influence fetal development. In: Kenner C, McGrath JM, Eds. Developmental Care of Newborns and Infants: A guide for health professionals. St Louis: Mosby; 2004. p. 131-56

11 McGrath JM. Feeding. In: Kenner C, McGrath JM, Eds. Developmental Care of Newborns and Infants: A guide for health professionals. St Louis: Mosby; 2004. p. 321-42

12 Dodrill P, Donovan T, Cleghorn G, McMahon S, Davies PSW. Attainment of early feeding milestones in preterm neonates. J Perinatol 2008; 28 (8): 549-555

13 Metheny N. Minimizing respiratory complications of nasoenteric tube feedings: State of the science. Heart & Lung 1993; 22(3): 213-23

14 Dotson RG, Robinson RG, Pingleton SK. Gastroesophageal reflux with nasogastric tubes. Effect of nasogastric tube size. Am J Resp Crit Care Med 1994; 149(6): 1659-1662

15 Cataldi Betcher EL, Seltzer MH, Slocum BA, Jones KW. Complications occurring during enteral nutrition support: A prospective study. J Parenter Enteral Nutr 1983; 7(6): 546-552

16 Da Nobrega L, Boiron M, Henrot A, Saliba E. Acoustic study of swallowing behaviour in premature infants during tube-bottle-feeding and bottle-feeding period. Early Hum Dev 2004; 78(1): 53-60

17 Greenspan JS, Wolfson MR, Holt WJ, Shaffer TH. Neonatal gastric intubation: Differential respiratory effects between nasogastric and orogastric tubes. Pediatr Pulmonol 1990; 8(4): 254-258

18 Hawes J, McEwan P, McGuire W. Nasal versus oral route for placing feeding tubes in preterm or low birth weight infants. Cochrane Database Syst Rev. 2004 (3)

19 Haxhija EQ, Rosegger H, Prechtl HF. Vagal response to feeding tube insertion in preterm infants: Has the key been found? Early Hum Dev 1995; 41(1): 15-25

20 Mukhtar AI, Stothers JK. Cardiovascular effects of nasogastric tube feeding in the healthy preterm infant. Early Hum Dev 1982; 6(1): 25-30

21 Noviski N, Yehuda YB, Serour F, Gorenstein A, Mandelberg A. Does the size of nasogastric tubes affect gastroesophageal reflux in children? J Pediatr Gastro Nutrit 1999; 29(4): 448-451

22 Symington A, Ballantyne M, Pinelli J, Stevens B. Indwelling versus intermittent feeding tubes in premature neonates. J Obstet, Gynecol, Neonat Nurs 1995; 24(4): 321-326

23 Peter CS, Wiechers C, Bohnhorst B, Silny J, Poets CF. Influence of nasogastric tubes on gastroesophageal reflux in preterm infants: A multiple intraluminal impedance study. J Pediatr 2002; 141(2): 277-279

24 Rochat P, Goubet N, Shah BL. Enhanced sucking engagement by preterm infants during intermittent gavage feedings. J Dev Behav Pediatr 1997; 18(1): 22-26

25 Sands T, Glasson M, Berry A. Hazards of nasogastric tube insertion in the newborn infant. Lancet 1989; 334(8664): 680

26 Holden CE1, MacDonald A, Ward M, Ford K, Patchell C, Handy D, Chell M, Brown GB, Booth IW. Psychological preparation for nasogastric feeding in children. Br J Nurs. 1997; 6(7): 376-381

27 Tos M, Bonding P. Middle ear pressure during and after prolonged nasotracheal and/or nasogastric intubation. Acta Oto Laryngologica. 1977; 83(3-4): 353-359

28 Kamen RS. Impaired development of oral-motor functions required for normal oral feeding as a consequence of tube feeding during infancy. Adv Perit Dial 1990; 6: 276-278

29 Michaelis CA, Warzak WJ, Stanek K, Van Riper C. Parental and professional perceptions of problems associated with long-term pediatric home tube feeding. J Am Diet Assoc 1992; 92(10): 1235-1238

30 Palmer MM. Weaning from gastrostomy tube feeding: Commentary on oral aversion. Pediatr Nurs 1998; 24(5): 475-478

31 Senez C, Guys JM, Mancini J, Paz Paredes A, Lena G, Choux M. Weaning children from tube to oral feeding. Childs Nerv Syst 1996; 12(10): 590-594

32 Vogel S. Oral motor and feeding problems in the tube fed infant: Suggested treatment strategies for the occupational therapist. Occ Ther Health Care. 1986; 3: 63-79

33 Warady BA, Kriley M, Belden B, Hellerstein S, Alan U. Nutritional and behavioural aspects of nasogastric tube feeding in infants receiving chronic peritoneal dialysis. Adv Perit Dial 1990; 6: 265-268

34 Dello Strologo L, Principato F, Sinibaldi D, Appiani AC, Terzi F, Dartois AM, Rizzoni G. Feeding dysfunction in infants with severe chronic renal failure after long-term nasogastric tube feeding. Pediatr Nephrol 1997; 11(1): 84-86

35 Dodrill P, McMahon S, Ward E, Weir K, Donovan T, Riddle B. Long-term oral sensitivity and feeding skills of low-risk pre-term infants. Early Hum Dev 2004; 76(1): 23-37

36 Erenberg A, Nowak AJ. Palatal groove formation in neonates and infants with orotracheal tubes. Am J Dis Child 1984; 138(10): 974-975

37 Molteni RA, Bumstead DH. Development and severity of palatal grooves in orally intubated newborns. Effect of ‘soft’ endotracheal tubes. Am J Dis Child 1986; 140(4): 357-359

38 Abraham SS, Wolf EL. Swallowing physiology of toddlers with long-term tracheostomies: A preliminary study. Dysphagia 2000; 15(4): 206-212

39 DeVita MA, Spierer Rundback L. Swallowing disorders in patients with prolonged orotracheal intubation or tracheostomy tubes. Crit Care Med 1990; 18(12): 1328-1330

40 Ash SP, Moss JP. An investigation of the features of the pre-term infant palate and the effect of prolonged orotracheal intubation with and without protective appliances. Br J Orthod 1987; 14(4): 253-261

41 Borowitz SM, Borowitz KC. Oral dysfunction following Nissen fundoplication. Dysphagia 1992; 7(4): 234-237

42 Logemann J. Evaluation and treatment of swallowing disorders 2nd Ed. Austin, Tx: PRO-ED; 1998

43 Menon AP, Schefft GL, Thach BT. Frequency and significance of swallowing during prolonged apnea in infants. Am Rev Respir Dis 1984; 130(6): 969-973

44 Thach BT, Menon A. Pulmonary protective mechanisms in human infants. Am Rev Respir Dis 1985; 131(5): S55-8

45 Fucile S, Gisel EG, Lau C. Effect of an oral stimulation program on sucking skill maturation of preterm infants. Dev Med Child Neurol 2005 Mar; 47(3): 158-162

46 Barlow SM, Finan DS, Lee J, Chu S. Synthetic orocutaneous stimulation entrains preterm infants with feeding difficulties to suck. J Perinatol 2008; 28: 541-548

47 Dodrill P. Feeding difficulties in preterm neonates. Infant, Child, & Adolescent Nutrition 2011; 3(6): 324-331

48 Morgan AT, Dodrill P, Ward EC. Interventions for oropharyngeal dysphagia in children with neurological impairment. Cochrane Database Syst Rev 2012 Oct 17; 10: CD009456. doi:10.1002/14651858.CD009456.pub2

49 Thoyre SM, Holditch-Davis D, Schwartz TA, Melendez Roman CR, Nix W. Coregulated approach to feeding preterm infants with lung disease: effects during feeding. Nurs Res. 2012 Jul-Aug; 61(4):242-51. doi: 10.1097/NNR.0b013e31824b02ad.

50 Dawson JA, Myers LR, Moorhead A, Jacobs SE, Ong K, Salo F, Murray S, Donath S, Davis PG. A randomised trial of two techniques for bottle feeding preterm infants. J Paediatr Child Health. 2013 Jun; 49(6): 462-466

51 Sharp WG, Jaquess DL, Morton JF, Herzinger CV. Pediatric Feeding Disorders: A Quantitative Synthesis of Treatment Outcomes. Clinical Child and Family Psychology Review 2010; 13(4): 348-365

52 Kerwin ME. Empirically supported treatments in pediatric psychology: severe feeding problems. J Pediatr Psychol 1999 Jun; 24(3): 193-214; discussion 215-216

53 Marshall J, Ware R, Ziviani J, Hill RJ, Dodrill P. Efficacy of interventions to improve feeding difficulties in children with autism spectrum disorders: a systematic review and meta-analysis. Child: Care, Health and Development, 2014 (in press).

Peer reviewer: Bernice Mathisen, Associate Professor Bernice Mathisen, Head of Speech Pathology, LaTrobe Rural Health School, Bendigo, Australia.


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