Rotavirus infection: This is a common cause of gastroenteritis in infants, characterized by high fever, diarrhea, and fatigue. The symptoms presented are typical for rotavirus infection, which is highly contagious and prevalent in this age group.

Norovirus infection: Similar to rotavirus, norovirus is a common cause of viral gastroenteritis in infants, leading to symptoms like high fever, diarrhea, and fatigue.
Adenovirus infection: Adenoviruses can cause a range of illnesses, including gastroenteritis, which would explain June's symptoms.
Astrovirus infection: Although less common than rotavirus or norovirus, astrovirus can also cause gastroenteritis in infants, presenting with similar symptoms.

Bacterial gastroenteritis (e.g., Salmonella, Shigella): While less likely than viral causes, bacterial gastroenteritis can be severe and requires prompt antibiotic treatment. Missing this diagnosis could lead to severe complications.
Intussusception: Although more commonly associated with abdominal pain and bloody stools, intussusception can sometimes present with nonspecific symptoms like fever and diarrhea. It's a medical emergency that requires immediate attention.
Sepsis: In infants, any infection can quickly escalate to sepsis, a life-threatening condition. Early recognition and treatment are crucial.

Food poisoning: While less common in infants, food poisoning from contaminated formula or food could present with similar symptoms.
Inflammatory bowel disease (IBD): Although rare in infants, conditions like Crohn's disease or ulcerative colitis could present with chronic diarrhea and fever.
Immunodeficiency: Underlying immunodeficiency conditions could predispose June to more severe or unusual infections, presenting with persistent or recurrent fever and diarrhea.